CVE-2026-23455 (GCVE-0-2026-23455)

Vulnerability from cvelistv5 – Published: 2026-04-03 15:15 – Updated: 2026-04-27 14:02
VLAI?
Title
netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: check for zero length in DecodeQ931() In DecodeQ931(), the UserUserIE code path reads a 16-bit length from the packet, then decrements it by 1 to skip the protocol discriminator byte before passing it to DecodeH323_UserInformation(). If the encoded length is 0, the decrement wraps to -1, which is then passed as a large value to the decoder, leading to an out-of-bounds read. Add a check to ensure len is positive after the decrement.
Severity ?
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < 2121f5fbe88daff0f1fc5bc47d359426c74b86b0 (git)
Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < 65fa92f79677858b14b9e4b7275f26639afe2710 (git)
Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < 495e97af9e7249ee02b72bb1d0848a6efc3700f4 (git)
Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < f5e4f4e4cdb75ec36802059a94195a31f193da60 (git)
Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < 633e8f87dad32263f6a57dccdb873f042c062111 (git)
Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < 9d00fe7d6d7c5b5f1065a6e042b54f2e44bd6df8 (git)
Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < b652b05d51003ac074b912684f9ec7486231717b (git)
Affected: 5e35941d990123f155b02d5663e51a24f816b6f3 , < f173d0f4c0f689173f8cdac79991043a4a89bf66 (git)
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    Linux Linux Affected: 2.6.17
Unaffected: 0 , < 2.6.17 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.167 , ≤ 6.1.* (semver)
Unaffected: 6.6.130 , ≤ 6.6.* (semver)
Unaffected: 6.12.78 , ≤ 6.12.* (semver)
Unaffected: 6.18.20 , ≤ 6.18.* (semver)
Unaffected: 6.19.10 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
            "net/netfilter/nf_conntrack_h323_asn1.c"
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.



Detection rules are retrieved from Rulezet.