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netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read parse_dcc() treats data_end as an inclusive end pointer, but its only caller passes data_limit = ib_ptr + datalen, which points one past the last valid byte. The newline search loop iterates while tmp <= data_end, so when no newline is present, *tmp is read at tmp == data_end, one byte beyond the region filled by skb_header_pointer(). irc_buffer is kmalloc'd as MAX_SEARCH_SIZE + 1 bytes and datalen is capped at MAX_SEARCH_SIZE, so the stray read does not fault. The byte is uninitialized or stale; if it contains an ASCII digit, simple_strtoul will consume it and produce a wrong DCC IP or port in the conntrack expectation. The extra allocation byte is also a fragile guard: if the cap or allocation size changes, this becomes a real out-of-bounds read. Change the loop and its post-loop check to use strict less-than, consistent with the caller's exclusive-end convention. Update the function comment accordingly.

Announced Source revision 1
Original source ↗

CVE-2026-80603

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-80603

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "437e0a3854b3a44ec15afa9ab88ec215adf3a2fd",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "2b70f61f569bb29acb380e6f616a1bbdee15668f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "2393f0bd7a467ad475598f3a5b9de27ca36e3037",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "aff589556ed772cb1c0c2d7b4d91ec45c0c39416",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "eeef3b81f449560653662df2dde6f6fe247c5365",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/netfilter/nf_conntrack_irc.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.12"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.12",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.261",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.212",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/netfilter/nf_conntrack_irc.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-80603

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#34342 · Revision 1
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Publisher date
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