{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "packageName": "ash_authentication",
          "packageURL": "pkg:hex/ash_authentication",
          "product": "ash_authentication",
          "repo": "https://github.com/team-alembic/ash_authentication",
          "vendor": "team-alembic",
          "versions": [
            {
              "lessThan": "4.15.0",
              "status": "affected",
              "version": "0.2.0",
              "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",
          "packageName": "team-alembic/ash_authentication",
          "packageURL": "pkg:github/team-alembic/ash_authentication",
          "product": "ash_authentication",
          "repo": "https://github.com/team-alembic/ash_authentication",
          "vendor": "team-alembic",
          "versions": [
            {
              "changes": [
                {
                  "at": "872db454405ecad4fcdabd9ff3d8755d1d6a69ae",
                  "status": "unaffected"
                },
                {
                  "at": "3e1d452cbf1564e87f5f97be882b66fe25af7cfa",
                  "status": "unaffected"
                }
              ],
              "lessThan": "*",
              "status": "affected",
              "version": "a939dde9b917c072cdf10c4b0913a9886a4b0231",
              "versionType": "git"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eExploitation for account takeover requires a server-side session store (ETS, Mnesia, Redis or a database), where the cookie carries a stable session identifier, and a position from which the attacker can plant that cookie in the victim\u0027s browser: cookie tossing from a sibling subdomain, an HTTP host without HSTS, or a shared or kiosk browser.\u003c/p\u003e\n\u003cp\u003ePhoenix defaults to the signed cookie store, and neither package\u0027s installer changes it. Under that store the authenticated session lives in the re-signed cookie delivered only to the victim, so a planted pre-authentication copy does not become an authenticated session. Attacker-planted session contents, such as a \u003ccode\u003ereturn_to\u003c/code\u003e value, still survive into the authenticated session there.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "Exploitation for account takeover requires a server-side session store (ETS, Mnesia, Redis or a database), where the cookie carries a stable session identifier, and a position from which the attacker can plant that cookie in the victim\u0027s browser: cookie tossing from a sibling subdomain, an HTTP host without HSTS, or a shared or kiosk browser.\n\nPhoenix defaults to the signed cookie store, and neither package\u0027s installer changes it. Under that store the authenticated session lives in the re-signed cookie delivered only to the victim, so a planted pre-authentication copy does not become an authenticated session. Attacker-planted session contents, such as a `return_to` value, still survive into the authenticated session there."
            }
          ],
          "value": "Exploitation for account takeover requires a server-side session store (ETS, Mnesia, Redis or a database), where the cookie carries a stable session identifier, and a position from which the attacker can plant that cookie in the victim\u0027s browser: cookie tossing from a sibling subdomain, an HTTP host without HSTS, or a shared or kiosk browser.\n\nPhoenix defaults to the signed cookie store, and neither package\u0027s installer changes it. Under that store the authenticated session lives in the re-signed cookie delivered only to the victim, so a planted pre-authentication copy does not become an authenticated session. Attacker-planted session contents, such as a return_to value, still survive into the authenticated session there."
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.15.0",
                  "versionStartIncluding": "0.2.0",
                  "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
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              "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": "2026-09-17T05:24:11.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eSession Fixation vulnerability in team-alembic ash_authentication allows an attacker who can plant a session identifier in a victim\u0027s browser to hold an authenticated session once that victim signs in.\u003c/p\u003e\n\u003cp\u003e\u003ccode\u003eAshAuthentication.Plug.Helpers.store_in_session/2\u003c/code\u003e writes the authenticated subject into the existing session with \u003ccode\u003ePlug.Conn.put_session/3\u003c/code\u003e and never calls \u003ccode\u003ePlug.Conn.configure_session(renew: true)\u003c/code\u003e, so the identifier the visitor arrived with carries into their authenticated session. Every authentication event reaches this one function: the default \u003ccode\u003esuccess/4\u003c/code\u003e injected by \u003ccode\u003eAshAuthentication.Phoenix.Controller.__using__/1\u003c/code\u003e, the \u003ccode\u003eAuthController\u003c/code\u003e emitted by \u003ccode\u003emix ash_authentication_phoenix.install\u003c/code\u003e, and remember-me auto-login. \u003ccode\u003eAshAuthentication.Phoenix.Plug.store_in_session/2\u003c/code\u003e is a \u003ccode\u003edefdelegate\u003c/code\u003e to it. Logout does not close the window either, because \u003ccode\u003eclear_session/2\u003c/code\u003e ends with \u003ccode\u003ePlug.Conn.clear_session/1\u003c/code\u003e, which clears session contents but leaves the identifier intact, so a planted identifier survives a logout-then-login cycle.\u003c/p\u003e\n\u003cp\u003eThis issue affects ash_authentication: from 0.2.0 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": "Session Fixation vulnerability in team-alembic ash_authentication allows an attacker who can plant a session identifier in a victim\u0027s browser to hold an authenticated session once that victim signs in.\n\n`AshAuthentication.Plug.Helpers.store_in_session/2` writes the authenticated subject into the existing session with `Plug.Conn.put_session/3` and never calls `Plug.Conn.configure_session(renew: true)`, so the identifier the visitor arrived with carries into their authenticated session. Every authentication event reaches this one function: the default `success/4` injected by `AshAuthentication.Phoenix.Controller.__using__/1`, the `AuthController` emitted by `mix ash_authentication_phoenix.install`, and remember-me auto-login. `AshAuthentication.Phoenix.Plug.store_in_session/2` is a `defdelegate` to it. Logout does not close the window either, because `clear_session/2` ends with `Plug.Conn.clear_session/1`, which clears session contents but leaves the identifier intact, so a planted identifier survives a logout-then-login cycle.\n\nThis issue affects ash_authentication: from 0.2.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."
            }
          ],
          "value": "Session Fixation vulnerability in team-alembic ash_authentication allows an attacker who can plant a session identifier in a victim\u0027s browser to hold an authenticated session once that victim signs in.\n\nAshAuthentication.Plug.Helpers.store_in_session/2 writes the authenticated subject into the existing session with Plug.Conn.put_session/3 and never calls Plug.Conn.configure_session(renew: true), so the identifier the visitor arrived with carries into their authenticated session. Every authentication event reaches this one function: the default success/4 injected by AshAuthentication.Phoenix.Controller.__using__/1, the AuthController emitted by mix ash_authentication_phoenix.install, and remember-me auto-login. AshAuthentication.Phoenix.Plug.store_in_session/2 is a defdelegate to it. Logout does not close the window either, because clear_session/2 ends with Plug.Conn.clear_session/1, which clears session contents but leaves the identifier intact, so a planted identifier survives a logout-then-login cycle.\n\nThis issue affects ash_authentication: from 0.2.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-61",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eAn attacker holding a session identifier they planted before the victim signed in gains that victim\u0027s authenticated session, and with it full account takeover, in deployments using a server-side session store.\u003c/p\u003e"
                },
                {
                  "base64": false,
                  "type": "text/markdown",
                  "value": "An attacker holding a session identifier they planted before the victim signed in gains that victim\u0027s authenticated session, and with it full account takeover, in deployments using a server-side session store."
                }
              ],
              "value": "An attacker holding a session identifier they planted before the victim signed in gains that victim\u0027s authenticated session, and with it full account takeover, in deployments using a server-side session store."
            }
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        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 7.4,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "ACTIVE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/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-384",
              "description": "CWE-384 Session Fixation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T21:58:00.853Z",
        "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-v577-944g-7h3x"
        },
        {
          "name": "EEF CNA record for CVE-2026-86688",
          "tags": [
            "related"
          ],
          "url": "https://cna.erlef.org/cves/CVE-2026-86688.html"
        },
        {
          "name": "OSV record EEF-CVE-2026-86688",
          "tags": [
            "related"
          ],
          "url": "https://osv.dev/vulnerability/EEF-CVE-2026-86688"
        },
        {
          "name": "Introducing commit a939dde in team-alembic/ash_authentication",
          "tags": [
            "related"
          ],
          "url": "https://github.com/team-alembic/ash_authentication/commit/a939dde9b917c072cdf10c4b0913a9886a4b0231"
        },
        {
          "name": "Fix commit 872db45 in team-alembic/ash_authentication",
          "tags": [
            "patch"
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          "url": "https://github.com/team-alembic/ash_authentication/commit/872db454405ecad4fcdabd9ff3d8755d1d6a69ae"
        },
        {
          "name": "Fix commit 3e1d452 in team-alembic/ash_authentication",
          "tags": [
            "patch"
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          "url": "https://github.com/team-alembic/ash_authentication/commit/3e1d452cbf1564e87f5f97be882b66fe25af7cfa"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Session id is not renewed on authentication in ash_authentication, allowing session fixation",
      "workarounds": [
        {
          "lang": "en",
          "supportingMedia": [
            {
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              "type": "text/html",
              "value": "\u003cp\u003eCall \u003ccode\u003ePlug.Conn.configure_session(conn, renew: true)\u003c/code\u003e in your own \u003ccode\u003esuccess/4\u003c/code\u003e before \u003ccode\u003estore_in_session/2\u003c/code\u003e. This is a one-line change in application code and closes the controller sign-in path, though not remember-me auto-login, which does not pass through application code.\u003c/p\u003e\n\u003cp\u003eAdd \u003ccode\u003ePlug.Conn.configure_session(conn, drop: true)\u003c/code\u003e at sign-out so a planted identifier does not survive a logout-then-login cycle.\u003c/p\u003e"
            },
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              "type": "text/markdown",
              "value": "Call `Plug.Conn.configure_session(conn, renew: true)` in your own `success/4` before `store_in_session/2`. This is a one-line change in application code and closes the controller sign-in path, though not remember-me auto-login, which does not pass through application code.\n\nAdd `Plug.Conn.configure_session(conn, drop: true)` at sign-out so a planted identifier does not survive a logout-then-login cycle."
            }
          ],
          "value": "Call Plug.Conn.configure_session(conn, renew: true) in your own success/4 before store_in_session/2. This is a one-line change in application code and closes the controller sign-in path, though not remember-me auto-login, which does not pass through application code.\n\nAdd Plug.Conn.configure_session(conn, drop: true) at sign-out so a planted identifier does not survive a logout-then-login cycle."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
    "assignerShortName": "EEF",
    "cveId": "CVE-2026-86688",
    "datePublished": "2026-09-17T21:58:00.853Z",
    "dateReserved": "2026-09-17T00:30:01.485Z",
    "dateUpdated": "2026-09-17T21:58:00.853Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-86688\",\"sourceIdentifier\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\",\"published\":\"2026-09-17T22:17:04.180\",\"lastModified\":\"2026-09-17T22:17:04.180\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Session Fixation vulnerability in team-alembic ash_authentication allows an attacker who can plant a session identifier in a victim\u0027s browser to hold an authenticated session once that victim signs in.\\n\\nAshAuthentication.Plug.Helpers.store_in_session/2 writes the authenticated subject into the existing session with Plug.Conn.put_session/3 and never calls Plug.Conn.configure_session(renew: true), so the identifier the visitor arrived with carries into their authenticated session. Every authentication event reaches this one function: the default success/4 injected by AshAuthentication.Phoenix.Controller.__using__/1, the AuthController emitted by mix ash_authentication_phoenix.install, and remember-me auto-login. AshAuthentication.Phoenix.Plug.store_in_session/2 is a defdelegate to it. Logout does not close the window either, because clear_session/2 ends with Plug.Conn.clear_session/1, which clears session contents but leaves the identifier intact, so a planted identifier survives a logout-then-login cycle.\\n\\nThis issue affects ash_authentication: from 0.2.0 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:*:*:*:*:*:*:*:*\"],\"repo\":\"https://github.com/team-alembic/ash_authentication\",\"packageURL\":\"pkg:hex/ash_authentication\",\"versions\":[{\"version\":\"0.2.0\",\"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:*:*:*:*:*:*:*:*\"],\"repo\":\"https://github.com/team-alembic/ash_authentication\",\"packageURL\":\"pkg:github/team-alembic/ash_authentication\",\"versions\":[{\"version\":\"a939dde9b917c072cdf10c4b0913a9886a4b0231\",\"lessThan\":\"*\",\"versionType\":\"git\",\"status\":\"affected\",\"changes\":[{\"at\":\"872db454405ecad4fcdabd9ff3d8755d1d6a69ae\",\"status\":\"unaffected\"},{\"at\":\"3e1d452cbf1564e87f5f97be882b66fe25af7cfa\",\"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:A/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\":7.4,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"PRESENT\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"ACTIVE\",\"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-384\"}]}],\"references\":[{\"url\":\"https://cna.erlef.org/cves/CVE-2026-86688.html\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/commit/3e1d452cbf1564e87f5f97be882b66fe25af7cfa\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/commit/872db454405ecad4fcdabd9ff3d8755d1d6a69ae\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/commit/a939dde9b917c072cdf10c4b0913a9886a4b0231\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-v577-944g-7h3x\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"},{\"url\":\"https://osv.dev/vulnerability/EEF-CVE-2026-86688\",\"source\":\"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\"}]}}"
  }
}