CVE-2026-31427 (GCVE-0-2026-31427)

Vulnerability from cvelistv5 – Published: 2026-04-13 13:40 – Updated: 2026-05-11 22:08
VLAI
Title
netfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp process_sdp() declares union nf_inet_addr rtp_addr on the stack and passes it to the nf_nat_sip sdp_session hook after walking the SDP media descriptions. However rtp_addr is only initialized inside the media loop when a recognized media type with a non-zero port is found. If the SDP body contains no m= lines, only inactive media sections (m=audio 0 ...) or only unrecognized media types, rtp_addr is never assigned. Despite that, the function still calls hooks->sdp_session() with &rtp_addr, causing nf_nat_sdp_session() to format the stale stack value as an IP address and rewrite the SDP session owner and connection lines with it. With CONFIG_INIT_STACK_ALL_ZERO (default on most distributions) this results in the session-level o= and c= addresses being rewritten to 0.0.0.0 for inactive SDP sessions. Without stack auto-init the rewritten address is whatever happened to be on the stack. Fix this by pre-initializing rtp_addr from the session-level connection address (caddr) when available, and tracking via a have_rtp_addr flag whether any valid address was established. Skip the sdp_session hook entirely when no valid address exists.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < faa6ea32797a1847790514ff0da1be1d09771580 (git)
Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < 82baeb871e8f04906bc886273fdf0209e1754eb3 (git)
Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < 6e5e3c87b7e6212f1d8414fc2e4d158b01e12025 (git)
Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6 (git)
Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < 7edca70751b9bdb5b83eed53cde21eccf3c86147 (git)
Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < 01f34a80ac23ae90b1909b94b4ed05343a62f646 (git)
Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < 52fdda318ef2362fc5936385bcb8b3d0328ee629 (git)
Affected: 4ab9e64e5e3c0516577818804aaf13a630d67bc9 , < 6a2b724460cb67caed500c508c2ae5cf012e4db4 (git)
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Linux Linux Affected: 2.6.26
Unaffected: 0 , < 2.6.26 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.131 , ≤ 6.6.* (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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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.