{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.AshAuthentication.Plug.Helpers\u0027"
          ],
          "packageName": "ash_authentication",
          "packageURL": "pkg:hex/ash_authentication",
          "product": "ash_authentication",
          "programFiles": [
            "lib/ash_authentication/plug/helpers.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:sign_in_using_remember_me/3"
            },
            {
              "name": "\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:store_in_session/2"
            }
          ],
          "repo": "https://github.com/team-alembic/ash_authentication",
          "vendor": "team-alembic",
          "versions": [
            {
              "lessThan": "4.15.0",
              "status": "affected",
              "version": "4.10.0",
              "versionType": "semver"
            },
            {
              "lessThan": "5.0.0-rc.14",
              "status": "affected",
              "version": "5.0.0-rc.0",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
            "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.AshAuthentication.Plug.Helpers\u0027"
          ],
          "packageName": "team-alembic/ash_authentication",
          "packageURL": "pkg:github/team-alembic/ash_authentication",
          "product": "ash_authentication",
          "programFiles": [
            "lib/ash_authentication/plug/helpers.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:sign_in_using_remember_me/3"
            },
            {
              "name": "\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:store_in_session/2"
            }
          ],
          "repo": "https://github.com/team-alembic/ash_authentication",
          "vendor": "team-alembic",
          "versions": [
            {
              "changes": [
                {
                  "at": "b9568a53b438247238b1c5a4f49c8d84650f4bba",
                  "status": "unaffected"
                },
                {
                  "at": "9a34136b844abe179da1075067cf2835c64dcc12",
                  "status": "unaffected"
                }
              ],
              "lessThan": "*",
              "status": "affected",
              "version": "3d3de314692558d06ec13945f857f00514e95a8c",
              "versionType": "git"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eThe application must enable the \u003ccode\u003eremember_me\u003c/code\u003e strategy and run its per-request plug in the browser pipeline, with \u003ccode\u003erequire_token_presence_for_authentication?\u003c/code\u003e at its default of \u003ccode\u003efalse\u003c/code\u003e. Enabling that setting makes the guard read the key the session actually holds, which closes the issue.\u003c/p\u003e\n\u003cp\u003eThe attacker also needs a position from which to set a cookie in the victim\u0027s browser, such as cookie tossing from a sibling subdomain, an HTTP host without HSTS, or a shared or kiosk browser.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "The application must enable the `remember_me` strategy and run its per-request plug in the browser pipeline, with `require_token_presence_for_authentication?` at its default of `false`. Enabling that setting makes the guard read the key the session actually holds, which closes the issue.\n\nThe attacker also needs a position from which to set a cookie in the victim\u0027s browser, such as cookie tossing from a sibling subdomain, an HTTP host without HSTS, or a shared or kiosk browser."
            }
          ],
          "value": "The application must enable the remember_me strategy and run its per-request plug in the browser pipeline, with require_token_presence_for_authentication? at its default of false. Enabling that setting makes the guard read the key the session actually holds, which closes the issue.\n\nThe attacker also needs a position from which to set a cookie in the victim\u0027s browser, such as cookie tossing from a sibling subdomain, an HTTP host without HSTS, or a shared or kiosk browser."
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.15.0",
                  "versionStartIncluding": "4.10.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.0.0-rc.14",
                  "versionStartIncluding": "5.0.0-rc.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "AND"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Peter Ullrich"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "James Harton"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Jonatan M\u00e4nnchen / EEF"
        }
      ],
      "dateAssigned": "2026-09-17T14:23:56.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eAuthentication Bypass by Spoofing vulnerability in team-alembic ash_authentication allows an attacker who can plant a remember-me cookie in a victim\u0027s browser to replace that victim\u0027s authenticated session with one for the attacker\u0027s own account.\u003c/p\u003e\n\u003cp\u003e\u003ccode\u003eAshAuthentication.Plug.Helpers.sign_in_using_remember_me/3\u003c/code\u003e skips re-authenticating an already-signed-in visitor by checking the session for \u003ccode\u003e\"\u0026lt;subject_name\u0026gt;_token\"\u003c/code\u003e, but \u003ccode\u003estore_in_session/2\u003c/code\u003e writes that key only when \u003ccode\u003erequire_token_presence_for_authentication?\u003c/code\u003e is enabled and otherwise writes the bare subject name. At the default setting the guard therefore reads a key that is never written, its already-signed-in branch is unreachable, and the remember-me sign-in runs on every request through the per-request browser pipeline plug. A planted remember-me cookie is consequently honoured even for a visitor holding a live authenticated session, so whatever the victim enters afterwards lands in data the attacker controls. The read path in \u003ccode\u003eauthenticate_resource_from_session/4\u003c/code\u003e selects the key correctly, so the guard and the reader disagree about which key holds the session.\u003c/p\u003e\n\u003cp\u003eThis issue affects ash_authentication: from 4.10.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "Authentication Bypass by Spoofing vulnerability in team-alembic ash_authentication allows an attacker who can plant a remember-me cookie in a victim\u0027s browser to replace that victim\u0027s authenticated session with one for the attacker\u0027s own account.\n\n`AshAuthentication.Plug.Helpers.sign_in_using_remember_me/3` skips re-authenticating an already-signed-in visitor by checking the session for `\"\u003csubject_name\u003e_token\"`, but `store_in_session/2` writes that key only when `require_token_presence_for_authentication?` is enabled and otherwise writes the bare subject name. At the default setting the guard therefore reads a key that is never written, its already-signed-in branch is unreachable, and the remember-me sign-in runs on every request through the per-request browser pipeline plug. A planted remember-me cookie is consequently honoured even for a visitor holding a live authenticated session, so whatever the victim enters afterwards lands in data the attacker controls. The read path in `authenticate_resource_from_session/4` selects the key correctly, so the guard and the reader disagree about which key holds the session.\n\nThis issue affects ash_authentication: from 4.10.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."
            }
          ],
          "value": "Authentication Bypass by Spoofing vulnerability in team-alembic ash_authentication allows an attacker who can plant a remember-me cookie in a victim\u0027s browser to replace that victim\u0027s authenticated session with one for the attacker\u0027s own account.\n\nAshAuthentication.Plug.Helpers.sign_in_using_remember_me/3 skips re-authenticating an already-signed-in visitor by checking the session for \"\u003csubject_name\u003e_token\", but store_in_session/2 writes that key only when require_token_presence_for_authentication? is enabled and otherwise writes the bare subject name. At the default setting the guard therefore reads a key that is never written, its already-signed-in branch is unreachable, and the remember-me sign-in runs on every request through the per-request browser pipeline plug. A planted remember-me cookie is consequently honoured even for a visitor holding a live authenticated session, so whatever the victim enters afterwards lands in data the attacker controls. The read path in authenticate_resource_from_session/4 selects the key correctly, so the guard and the reader disagree about which key holds the session.\n\nThis issue affects ash_authentication: from 4.10.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-21",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eAn attacker who can set a remember-me cookie in a victim\u0027s browser silently replaces the victim\u0027s authenticated session with one for the attacker\u0027s own account, so data the victim subsequently enters is written to records the attacker controls. The victim is given no indication their identity changed.\u003c/p\u003e"
                },
                {
                  "base64": false,
                  "type": "text/markdown",
                  "value": "An attacker who can set a remember-me cookie in a victim\u0027s browser silently replaces the victim\u0027s authenticated session with one for the attacker\u0027s own account, so data the victim subsequently enters is written to records the attacker controls. The victim is given no indication their identity changed."
                }
              ],
              "value": "An attacker who can set a remember-me cookie in a victim\u0027s browser silently replaces the victim\u0027s authenticated session with one for the attacker\u0027s own account, so data the victim subsequently enters is written to records the attacker controls. The victim is given no indication their identity changed."
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
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          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-290",
              "description": "CWE-290 Authentication Bypass by Spoofing",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T21:57:50.146Z",
        "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "shortName": "EEF"
      },
      "references": [
        {
          "name": "GitHub Advisory",
          "tags": [
            "related",
            "vendor-advisory"
          ],
          "url": "https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-hh34-374j-pfr5"
        },
        {
          "name": "EEF CNA record for CVE-2026-76949",
          "tags": [
            "related"
          ],
          "url": "https://cna.erlef.org/cves/CVE-2026-76949.html"
        },
        {
          "name": "OSV record EEF-CVE-2026-76949",
          "tags": [
            "related"
          ],
          "url": "https://osv.dev/vulnerability/EEF-CVE-2026-76949"
        },
        {
          "name": "Introducing commit 3d3de31 in team-alembic/ash_authentication",
          "tags": [
            "related"
          ],
          "url": "https://github.com/team-alembic/ash_authentication/commit/3d3de314692558d06ec13945f857f00514e95a8c"
        },
        {
          "name": "Fix commit b9568a5 in team-alembic/ash_authentication",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/team-alembic/ash_authentication/commit/b9568a53b438247238b1c5a4f49c8d84650f4bba"
        },
        {
          "name": "Fix commit 9a34136 in team-alembic/ash_authentication",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/team-alembic/ash_authentication/commit/9a34136b844abe179da1075067cf2835c64dcc12"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Remember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacement",
      "workarounds": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eSet \u003ccode\u003erequire_token_presence_for_authentication? true\u003c/code\u003e on the authenticated resource\u0027s token configuration. \u003ccode\u003estore_in_session/2\u003c/code\u003e then writes the key the guard reads, so the already-signed-in branch fires and the remember-me sign-in no longer runs against a live session. Note this changes session storage semantics for the whole application and requires a token resource.\u003c/p\u003e\n\u003cp\u003eOtherwise remove the remember-me plug from the browser pipeline, which disables remember-me auto-login entirely.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "Set `require_token_presence_for_authentication? true` on the authenticated resource\u0027s token configuration. `store_in_session/2` then writes the key the guard reads, so the already-signed-in branch fires and the remember-me sign-in no longer runs against a live session. Note this changes session storage semantics for the whole application and requires a token resource.\n\nOtherwise remove the remember-me plug from the browser pipeline, which disables remember-me auto-login entirely."
            }
          ],
          "value": "Set require_token_presence_for_authentication? true on the authenticated resource\u0027s token configuration. store_in_session/2 then writes the key the guard reads, so the already-signed-in branch fires and the remember-me sign-in no longer runs against a live session. Note this changes session storage semantics for the whole application and requires a token resource.\n\nOtherwise remove the remember-me plug from the browser pipeline, which disables remember-me auto-login entirely."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
    "assignerShortName": "EEF",
    "cveId": "CVE-2026-76949",
    "datePublished": "2026-09-17T21:57:50.146Z",
    "dateReserved": "2026-09-17T05:30:01.744Z",
    "dateUpdated": "2026-09-17T21:57:50.146Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-76949\",\"sourceIdentifier\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\",\"published\":\"2026-09-17T22:17:03.883\",\"lastModified\":\"2026-09-17T22:17:03.883\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Authentication Bypass by Spoofing vulnerability in team-alembic ash_authentication allows an attacker who can plant a remember-me cookie in a victim\u0027s browser to replace that victim\u0027s authenticated session with one for the attacker\u0027s own account.\\n\\nAshAuthentication.Plug.Helpers.sign_in_using_remember_me/3 skips re-authenticating an already-signed-in visitor by checking the session for \\\"\u003csubject_name\u003e_token\\\", but store_in_session/2 writes that key only when require_token_presence_for_authentication? is enabled and otherwise writes the bare subject name. At the default setting the guard therefore reads a key that is never written, its already-signed-in branch is unreachable, and the remember-me sign-in runs on every request through the per-request browser pipeline plug. A planted remember-me cookie is consequently honoured even for a visitor holding a live authenticated session, so whatever the victim enters afterwards lands in data the attacker controls. The read path in authenticate_resource_from_session/4 selects the key correctly, so the guard and the reader disagree about which key holds the session.\\n\\nThis issue affects ash_authentication: from 4.10.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.\"}],\"affected\":[{\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\",\"affectedData\":[{\"vendor\":\"team-alembic\",\"product\":\"ash_authentication\",\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://repo.hex.pm\",\"packageName\":\"ash_authentication\",\"cpes\":[\"cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*\"],\"modules\":[\"\u0027Elixir.AshAuthentication.Plug.Helpers\u0027\"],\"programFiles\":[\"lib/ash_authentication/plug/helpers.ex\"],\"programRoutines\":[{\"name\":\"\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:sign_in_using_remember_me/3\"},{\"name\":\"\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:store_in_session/2\"}],\"repo\":\"https://github.com/team-alembic/ash_authentication\",\"packageURL\":\"pkg:hex/ash_authentication\",\"versions\":[{\"version\":\"4.10.0\",\"lessThan\":\"4.15.0\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.0.0-rc.0\",\"lessThan\":\"5.0.0-rc.14\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"team-alembic\",\"product\":\"ash_authentication\",\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://github.com\",\"packageName\":\"team-alembic/ash_authentication\",\"cpes\":[\"cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*\"],\"modules\":[\"\u0027Elixir.AshAuthentication.Plug.Helpers\u0027\"],\"programFiles\":[\"lib/ash_authentication/plug/helpers.ex\"],\"programRoutines\":[{\"name\":\"\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:sign_in_using_remember_me/3\"},{\"name\":\"\u0027Elixir.AshAuthentication.Plug.Helpers\u0027:store_in_session/2\"}],\"repo\":\"https://github.com/team-alembic/ash_authentication\",\"packageURL\":\"pkg:github/team-alembic/ash_authentication\",\"versions\":[{\"version\":\"3d3de314692558d06ec13945f857f00514e95a8c\",\"lessThan\":\"*\",\"versionType\":\"git\",\"status\":\"affected\",\"changes\":[{\"at\":\"b9568a53b438247238b1c5a4f49c8d84650f4bba\",\"status\":\"unaffected\"},{\"at\":\"9a34136b844abe179da1075067cf2835c64dcc12\",\"status\":\"unaffected\"}]}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X\",\"baseScore\":9.1,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"PRESENT\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"HIGH\",\"vulnIntegrityImpact\":\"HIGH\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}]},\"weaknesses\":[{\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-290\"}]}],\"references\":[{\"url\":\"https://cna.erlef.org/cves/CVE-2026-76949.html\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/commit/3d3de314692558d06ec13945f857f00514e95a8c\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/commit/9a34136b844abe179da1075067cf2835c64dcc12\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/commit/b9568a53b438247238b1c5a4f49c8d84650f4bba\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-hh34-374j-pfr5\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://osv.dev/vulnerability/EEF-CVE-2026-76949\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"}]}}"
  }
}