CVE-2026-31630 (GCVE-0-2026-31630)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:44 – Updated: 2026-04-24 14:44
VLAI?
Title
rxrpc: proc: size address buffers for %pISpc output
Summary
In the Linux kernel, the following vulnerability has been resolved: rxrpc: proc: size address buffers for %pISpc output The AF_RXRPC procfs helpers format local and remote socket addresses into fixed 50-byte stack buffers with "%pISpc". That is too small for the longest current-tree IPv6-with-port form the formatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a dotted-quad tail not only for v4mapped addresses, but also for ISATAP addresses via ipv6_addr_is_isatap(). As a result, a case such as [ffff:ffff:ffff:ffff:0:5efe:255.255.255.255]:65535 is possible with the current formatter. That is 50 visible characters, so 51 bytes including the trailing NUL, which does not fit in the existing char[50] buffers used by net/rxrpc/proc.c. Size the buffers from the formatter's maximum textual form and switch the call sites to scnprintf(). Changes since v1: - correct the changelog to cite the actual maximum current-tree case explicitly - frame the proof around the ISATAP formatting path instead of the earlier mapped-v4 example
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 75b54cb57ca34cbe7a87c6ac757c55360a624590 , < db297c78ce537c9ac96f0eda9b25ad72c8caefa9 (git)
Affected: 75b54cb57ca34cbe7a87c6ac757c55360a624590 , < 10ebed83f9f6414af4e85bc85ffaeda7effdd874 (git)
Affected: 75b54cb57ca34cbe7a87c6ac757c55360a624590 , < a44ce6aa2efb61fe44f2cfab72bb01544bbca272 (git)
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    Linux Linux Affected: 4.9
Unaffected: 0 , < 4.9 (semver)
Unaffected: 6.18.23 , ≤ 6.18.* (semver)
Unaffected: 6.19.13 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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          "programFiles": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: proc: size address buffers for %pISpc output\n\nThe AF_RXRPC procfs helpers format local and remote socket addresses into\nfixed 50-byte stack buffers with \"%pISpc\".\n\nThat is too small for the longest current-tree IPv6-with-port form the\nformatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a\ndotted-quad tail not only for v4mapped addresses, but also for ISATAP\naddresses via ipv6_addr_is_isatap().\n\nAs a result, a case such as\n\n  [ffff:ffff:ffff:ffff:0:5efe:255.255.255.255]:65535\n\nis possible with the current formatter. That is 50 visible characters, so\n51 bytes including the trailing NUL, which does not fit in the existing\nchar[50] buffers used by net/rxrpc/proc.c.\n\nSize the buffers from the formatter\u0027s maximum textual form and switch the\ncall sites to scnprintf().\n\nChanges since v1:\n- correct the changelog to cite the actual maximum current-tree case\n  explicitly\n- frame the proof around the ISATAP formatting path instead of the earlier\n  mapped-v4 example"
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        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/a44ce6aa2efb61fe44f2cfab72bb01544bbca272"
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      "title": "rxrpc: proc: size address buffers for %pISpc output",
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    "cveId": "CVE-2026-31630",
    "datePublished": "2026-04-24T14:44:46.606Z",
    "dateReserved": "2026-03-09T15:48:24.124Z",
    "dateUpdated": "2026-04-24T14:44:46.606Z",
    "state": "PUBLISHED"
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  }
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  • 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.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.