CVE-2026-89783 (GCVE-0-2026-89783)
Vulnerability from cvelistv5
Published
2026-09-16 08:48
Modified
2026-10-19 08:52
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full The depth check in xfrm6_input_addr() is off by one: if (1 + sp->len == XFRM_MAX_DEPTH) goto drop; ... sp->xvec[sp->len++] = x; xfrm_input() can leave sp->len == XFRM_MAX_DEPTH, and the transport-mode receive path re-enters IPv6 input via xfrm_trans_reinject() with that secpath preserved. If the inner packet carries a destination-options HAO option or a type-2 routing header, xfrm6_input_addr() is called with sp->len == XFRM_MAX_DEPTH; the check (1 + 6 == 6) is false, so sp->xvec[sp->len++] writes one slot past the 6-element xvec[]. The write stays within the sec_path allocation (invisible to KASAN); UBSAN_BOUNDS flags it and panics under panic_on_warn. Use "sp->len >= XFRM_MAX_DEPTH", matching xfrm_input(). This also restores one chain level the old check rejected at sp->len == 5. UBSAN: array-index-out-of-bounds in net/ipv6/xfrm6_input.c:309:10 index 6 is out of range for type 'xfrm_state *[6]'
References
Impacted products
Vendor Product Version
Linux Linux Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
Version: 9473e1f631de339c50bde1e3bd09e1045fe90fd5
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/xfrm6_input.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/xfrm6_input.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.25"
            },
            {
              "lessThan": "2.6.25",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
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                  "versionEndExcluding": "5.15.221",
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                  "vulnerable": true
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                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "2.6.25",
                  "vulnerable": true
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                {
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                  "versionEndExcluding": "6.12.110",
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full\n\nThe depth check in xfrm6_input_addr() is off by one:\n\n  if (1 + sp-\u003elen == XFRM_MAX_DEPTH)\n          goto drop;\n  ...\n  sp-\u003exvec[sp-\u003elen++] = x;\n\nxfrm_input() can leave sp-\u003elen == XFRM_MAX_DEPTH, and the transport-mode\nreceive path re-enters IPv6 input via xfrm_trans_reinject() with that\nsecpath preserved. If the inner packet carries a destination-options HAO\noption or a type-2 routing header, xfrm6_input_addr() is called with\nsp-\u003elen == XFRM_MAX_DEPTH; the check (1 + 6 == 6) is false, so\nsp-\u003exvec[sp-\u003elen++] writes one slot past the 6-element xvec[]. The write\nstays within the sec_path allocation (invisible to KASAN); UBSAN_BOUNDS\nflags it and panics under panic_on_warn.\n\nUse \"sp-\u003elen \u003e= XFRM_MAX_DEPTH\", matching xfrm_input(). This also\nrestores one chain level the old check rejected at sp-\u003elen == 5.\n\n  UBSAN: array-index-out-of-bounds in net/ipv6/xfrm6_input.c:309:10\n  index 6 is out of range for type \u0027xfrm_state *[6]\u0027"
        }
      ],
      "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 on the IPv6 receive path: remote ESP/AH packets are processed by xfrm_input() until the secpath is full, then xfrm_trans_reinject() re-enters ip6_rcv_finish so an inner destopt HAO or type-2 routing header reaches xfrm6_input_addr() on internet-facing IPsec/MIP6 VPN and home-agent endpoints.\nAC:L - Once a max-depth transport-mode IPsec bundle and a MIP6 destopt or routing state are present, a peer sending nested IPsec then an inner HAO or type-2 RH deterministically bypasses the off-by-one check (1+6!=6) and writes xvec[6]; no race or attacker-uncontrollable layout is required.\nPR:N - No local account or capability on the victim is required. A remote IPsec/MIP6 peer triggers the overflow with packets accepted by already-installed SAs; creating those SAs is a deployment precondition rather than attacker privilege on the host.\nUI:N - Packets are processed in NAPI/softirq and the deferred xfrm_trans_reinject workqueue with no victim action such as mounting a filesystem, opening a file, or otherwise interacting with the host.\nS:U - The out-of-bounds write corrupts the skb sec_path in the host kernel that processed the packet; this is standard kernel memory corruption, not a VM escape, IOMMU bypass, or other cross-authority boundary.\nC:H - The overflow writes a kernel xfrm_state pointer past xvec[] into the adjacent xfrm_offload object and sets len to 7, so later xvec walks and teardown treat that overlapping memory as a state pointer, giving a memory-corruption disclosure primitive.\nI:H - This is an out-of-bounds write of a kernel pointer one slot past the 6-element xvec[] into ovec, which per kernel CVSS guidance is high integrity impact and can be shaped toward control-flow hijacking.\nA:H - UBSAN_BOUNDS flags the overflow and panics under panic_on_warn, and the corrupted sec_path (len=7 overlapping ovec) can oops during later xvec iteration or skb_ext teardown, fully denying availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:52:35.697Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/91fc387f63c00ddfb5221127a17bac97549a8343"
        },
        {
          "url": "https://git.kernel.org/stable/c/68e8737fe8e72f085c608cff322b3d2de8340af1"
        },
        {
          "url": "https://git.kernel.org/stable/c/8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77"
        },
        {
          "url": "https://git.kernel.org/stable/c/bdcda866c89f9a8b1acdabf02d26cde9fbe501d8"
        },
        {
          "url": "https://git.kernel.org/stable/c/48996649222e95008cdb98cd58579e3fc8e5ee06"
        },
        {
          "url": "https://git.kernel.org/stable/c/0f679e0523ddfff3fb554336ceb874b0e51e9cd3"
        },
        {
          "url": "https://git.kernel.org/stable/c/5f35a29a5eed3d80befd32050843ac88dea3d61a"
        },
        {
          "url": "https://git.kernel.org/stable/c/5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc"
        }
      ],
      "title": "xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89783",
    "datePublished": "2026-09-16T08:48:21.761Z",
    "dateReserved": "2026-09-11T19:38:34.765Z",
    "dateUpdated": "2026-10-19T08:52:35.697Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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