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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

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{
  "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"
    }
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  "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: 2026-10-16 19:06

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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-16 19:02 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6666 records in the last 180 days details

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)

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                "id": "CVE-2026-74611",
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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.

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