Vulnerability-Lookup

GHSA-G4XP-J3J4-VMRQ

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31

Details

In the Linux kernel, the following vulnerability has been resolved:

tls: rx: restore msg_iter before TLS 1.3 optimistic retry

tls_decrypt_sg() advances msg->msg_iter when it maps user pages for the optimistic TLS 1.3 zero-copy path. If the decrypted record turns out not to be unpadded application data, tls_decrypt_sw() retries into a kernel skb, but leaves the iterator advanced.

The subsequent copy from the skb then writes decrypted bytes again at a later point in the caller iovecs while recvmsg() reports only the post-retry length. A TLS peer can trigger this after the receiver enables TLS_RX_EXPECT_NO_PAD.

Revert the iterator by the number of bytes consumed by the optimistic mapping before retrying without zero-copy.

Add a selftest which sends a TLS 1.3 control record with TLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not overwrite later iovecs beyond the returned length.

Severity

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-74611"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:33Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: rx: restore msg_iter before TLS 1.3 optimistic retry\n\ntls_decrypt_sg() advances msg-\u003emsg_iter when it maps user pages for\nthe optimistic TLS 1.3 zero-copy path. If the decrypted record turns\nout not to be unpadded application data, tls_decrypt_sw() retries into\na kernel skb, but leaves the iterator advanced.\n\nThe subsequent copy from the skb then writes decrypted bytes again at\na later point in the caller iovecs while recvmsg() reports only the\npost-retry length. A TLS peer can trigger this after the receiver\nenables TLS_RX_EXPECT_NO_PAD.\n\nRevert the iterator by the number of bytes consumed by the optimistic\nmapping before retrying without zero-copy.\n\nAdd a selftest which sends a TLS 1.3 control record with\nTLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not\noverwrite later iovecs beyond the returned length.",
  "id": "GHSA-g4xp-j3j4-vmrq",
  "modified": "2026-08-25T06:31:22Z",
  "published": "2026-08-22T18:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74611"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1c8629651cb54f7b51db8fc0b1a9944e4a4b0f5e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3c837266a734e2a22b24d2d567404a501d405835"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/68787940274ec89f41dc91b1a68ee1a16a90735f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-74611 (GCVE-0-2026-74611)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:31 – Updated: 2026-08-25 05:40

Title

tls: rx: restore msg_iter before TLS 1.3 optimistic retry

Summary

In the Linux kernel, the following vulnerability has been resolved: tls: rx: restore msg_iter before TLS 1.3 optimistic retry tls_decrypt_sg() advances msg->msg_iter when it maps user pages for the optimistic TLS 1.3 zero-copy path. If the decrypted record turns out not to be unpadded application data, tls_decrypt_sw() retries into a kernel skb, but leaves the iterator advanced. The subsequent copy from the skb then writes decrypted bytes again at a later point in the caller iovecs while recvmsg() reports only the post-retry length. A TLS peer can trigger this after the receiver enables TLS_RX_EXPECT_NO_PAD. Revert the iterator by the number of bytes consumed by the optimistic mapping before retrying without zero-copy. Add a selftest which sends a TLS 1.3 control record with TLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not overwrite later iovecs beyond the returned length.

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/68787940274ec89f4…
https://git.kernel.org/stable/c/3c837266a734e2a22…
https://git.kernel.org/stable/c/1c8629651cb54f7b5…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: ce61327ce989b63c0bd1cc7afee00e218ee696ac , < 68787940274ec89f41dc91b1a68ee1a16a90735f (git) Affected: ce61327ce989b63c0bd1cc7afee00e218ee696ac , < 3c837266a734e2a22b24d2d567404a501d405835 (git) Affected: ce61327ce989b63c0bd1cc7afee00e218ee696ac , < 1c8629651cb54f7b51db8fc0b1a9944e4a4b0f5e (git)
Linux	Linux	Affected: 6.0 Unaffected: 0 , < 6.0 (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/tls/tls_sw.c",
            "tools/testing/selftests/net/tls.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "68787940274ec89f41dc91b1a68ee1a16a90735f",
              "status": "affected",
              "version": "ce61327ce989b63c0bd1cc7afee00e218ee696ac",
              "versionType": "git"
            },
            {
              "lessThan": "3c837266a734e2a22b24d2d567404a501d405835",
              "status": "affected",
              "version": "ce61327ce989b63c0bd1cc7afee00e218ee696ac",
              "versionType": "git"
            },
            {
              "lessThan": "1c8629651cb54f7b51db8fc0b1a9944e4a4b0f5e",
              "status": "affected",
              "version": "ce61327ce989b63c0bd1cc7afee00e218ee696ac",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/tls/tls_sw.c",
            "tools/testing/selftests/net/tls.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.45",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: rx: restore msg_iter before TLS 1.3 optimistic retry\n\ntls_decrypt_sg() advances msg-\u003emsg_iter when it maps user pages for\nthe optimistic TLS 1.3 zero-copy path. If the decrypted record turns\nout not to be unpadded application data, tls_decrypt_sw() retries into\na kernel skb, but leaves the iterator advanced.\n\nThe subsequent copy from the skb then writes decrypted bytes again at\na later point in the caller iovecs while recvmsg() reports only the\npost-retry length. A TLS peer can trigger this after the receiver\nenables TLS_RX_EXPECT_NO_PAD.\n\nRevert the iterator by the number of bytes consumed by the optimistic\nmapping before retrying without zero-copy.\n\nAdd a selftest which sends a TLS 1.3 control record with\nTLS_RX_EXPECT_NO_PAD enabled and verifies that recvmsg() does not\noverwrite later iovecs beyond the returned length."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is in kTLS software RX (tls_decrypt_sw/tls_sw_recvmsg) and is driven by TLS 1.3 records received from a remote TCP peer; per kernel CNA guidance, kTLS flaws triggered by peer ciphertext on an established connection are Network-reachable (e.g., malicious client to nginx/HAProxy/NVMe-oF-TLS server).\nAC:L - Once the receiver has TLS 1.3 kTLS RX with TLS_RX_EXPECT_NO_PAD, a remote peer can deterministically trigger the optimistic-decrypt retry by sending a non-application-data inner record (handshake/alert/KeyUpdate) or padded data; no race, special heap layout, or rare kernel build is required.\nPR:N - Exploitation requires only being the remote TLS peer on an established kTLS connection; the attacker needs no credentials or Linux capabilities on the victim host. TLS_RX_EXPECT_NO_PAD is a receiver-side performance option set by the service, not an attacker privilege gate.\nUI:N - No victim user action beyond normal automated server operation (maintaining a TLS session and calling recvmsg on kTLS sockets). The attacker triggers the flaw solely by sending protocol-valid TLS records over the network.\nS:U - The out-of-bounds write corrupts user-space iovec buffers of the process owning the kTLS socket within the same security authority; it does not cross a VM, IOMMU, or sandbox boundary to another security domain.\nC:H - skb_copy_datagram_msg writes decrypted peer-controlled bytes past the recvmsg-reported length into adjacent user buffers. This memory corruption can be leveraged for information disclosure via heap/stack grooming even though the immediate primitive is a write.\nI:H - The remote peer controls the decrypted payload written out-of-bounds (up to a full TLS record, roughly 16 KiB) into later iovecs while recvmsg under-reports bytes copied, giving a reliable user-space memory corruption primitive suitable for control-flow or data hijack in privileged daemons.\nA:H - Corrupting adjacent application buffers in kTLS-enabled daemons (web proxies, storage targets, RPC endpoints) can crash workers or destabilize the service; the silent mismatch between returned length and bytes written also enables persistent denial of service on long-lived connections."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:40:37.263Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/68787940274ec89f41dc91b1a68ee1a16a90735f"
        },
        {
          "url": "https://git.kernel.org/stable/c/3c837266a734e2a22b24d2d567404a501d405835"
        },
        {
          "url": "https://git.kernel.org/stable/c/1c8629651cb54f7b51db8fc0b1a9944e4a4b0f5e"
        }
      ],
      "title": "tls: rx: restore msg_iter before TLS 1.3 optimistic retry",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74611",
    "datePublished": "2026-08-22T15:31:57.534Z",
    "dateReserved": "2026-08-15T05:44:03.920Z",
    "dateUpdated": "2026-08-25T05:40:37.263Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-G4XP-J3J4-VMRQ

CVE-2026-74611 (GCVE-0-2026-74611)

Tags

Sightings

Nomenclature