FKIE_CVE-2026-98549

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-30 13:21
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: tcp: prevent collapsing skbs across boundary in rtx queue tcp_write_collapse_fence() sets TCP_SKB_CB(skb)->eor = 1 on tcp_write_queue_tail(sk) to prevent skbs queued after a switch to device encryption from being collapsed into earlier skbs. The fence is a no-op if all earlier data has already been transmitted when the switch happens: sk->sk_write_queue is empty. The not yet acknowledged earlier skbs wait in sk->tcp_rtx_queue with eor 0. On a subsequent retransmit or SACK shift, tcp_retrans_try_collapse() or tcp_shift_skb_data() can then merge an skb queued after the switch into one queued before it. Both users of the fence are affected: - psp: devices only encrypt skbs with skb->decrypted set. The merged skb keeps decrypted = 0 from the earlier skb, so merged data sent after psp_sock_assoc_set_tx() is retransmitted in cleartext. - tls device offload: the merged skb straddles the start marker set in tls_set_device_offload(). The software fallback (fill_sg_in() returns -EINVAL) and the mlx5, nfp and funeth drivers cannot handle such an skb and drop it. Every retransmit rebuilds the same skb, so the connection stalls. Fix this in two places, for defense in depth: 1. Fall back to tcp_rtx_queue_tail(sk) in tcp_write_collapse_fence() when tcp_write_queue_tail(sk) is NULL. 2. Check !skb_cmp_decrypted(to, from) in tcp_skb_can_collapse(), as tcp_skb_can_collapse_rx() does on receive. skb_shift(), which both collapse paths call, already has a DEBUG_NET_WARN_ON_ONCE() for this condition.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/08e835f5ec6e261c79d8c39f8618b3af29e3b0da
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1ae7aee395245874d797890380d9192bd858fb7e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/533344a00ad968181e60d0980c076a9d0de57482
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7061aafc680e14e22b191f178b768886475f8524
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7ba87509c54cd519e7ed362e0c85e8431f066a18
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9e2a2f98e8c0197108c6d97a1fa43bfd89071c30
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bf785a303e5faad16439c563826a07cb811856c8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fc6d80eb504458d6416b75a94188b268c95c6533
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/tcp.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bf785a303e5faad16439c563826a07cb811856c8",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            },
            {
              "lessThan": "7061aafc680e14e22b191f178b768886475f8524",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            },
            {
              "lessThan": "533344a00ad968181e60d0980c076a9d0de57482",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            },
            {
              "lessThan": "9e2a2f98e8c0197108c6d97a1fa43bfd89071c30",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            },
            {
              "lessThan": "1ae7aee395245874d797890380d9192bd858fb7e",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            },
            {
              "lessThan": "7ba87509c54cd519e7ed362e0c85e8431f066a18",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            },
            {
              "lessThan": "08e835f5ec6e261c79d8c39f8618b3af29e3b0da",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            },
            {
              "lessThan": "fc6d80eb504458d6416b75a94188b268c95c6533",
              "status": "affected",
              "version": "e8f69799810c32dd40c6724d829eccc70baad07f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/net/tcp.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.18"
            },
            {
              "lessThan": "4.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: prevent collapsing skbs across boundary in rtx queue\n\ntcp_write_collapse_fence() sets TCP_SKB_CB(skb)-\u003eeor = 1 on\ntcp_write_queue_tail(sk) to prevent skbs queued after a switch to\ndevice encryption from being collapsed into earlier skbs.\n\nThe fence is a no-op if all earlier data has already been transmitted\nwhen the switch happens: sk-\u003esk_write_queue is empty. The not yet\nacknowledged earlier skbs wait in sk-\u003etcp_rtx_queue with eor 0.\n\nOn a subsequent retransmit or SACK shift, tcp_retrans_try_collapse() or\ntcp_shift_skb_data() can then merge an skb queued after the switch into\none queued before it.\n\nBoth users of the fence are affected:\n\n- psp: devices only encrypt skbs with skb-\u003edecrypted set. The merged skb\n  keeps decrypted = 0 from the earlier skb, so merged data sent after\n  psp_sock_assoc_set_tx() is retransmitted in cleartext.\n\n- tls device offload: the merged skb straddles the start marker set in\n  tls_set_device_offload(). The software fallback (fill_sg_in() returns\n  -EINVAL) and the mlx5, nfp and funeth drivers cannot handle such an\n  skb and drop it. Every retransmit rebuilds the same skb, so the\n  connection stalls.\n\nFix this in two places, for defense in depth:\n\n1. Fall back to tcp_rtx_queue_tail(sk) in tcp_write_collapse_fence()\n   when tcp_write_queue_tail(sk) is NULL.\n\n2. Check !skb_cmp_decrypted(to, from) in tcp_skb_can_collapse(), as\n   tcp_skb_can_collapse_rx() does on receive. skb_shift(), which both\n   collapse paths call, already has a DEBUG_NET_WARN_ON_ONCE() for this\n   condition."
    }
  ],
  "id": "CVE-2026-98549",
  "lastModified": "2026-10-30T13:21:15.940",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-10-18T16:17:06.913",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/08e835f5ec6e261c79d8c39f8618b3af29e3b0da"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1ae7aee395245874d797890380d9192bd858fb7e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/533344a00ad968181e60d0980c076a9d0de57482"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7061aafc680e14e22b191f178b768886475f8524"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7ba87509c54cd519e7ed362e0c85e8431f066a18"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9e2a2f98e8c0197108c6d97a1fa43bfd89071c30"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bf785a303e5faad16439c563826a07cb811856c8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fc6d80eb504458d6416b75a94188b268c95c6533"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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