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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-31427 Detail

Description

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.


Metrics

 
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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/01f34a80ac23ae90b1909b94b4ed05343a62f646 kernel.org Patch 
https://git.kernel.org/stable/c/52fdda318ef2362fc5936385bcb8b3d0328ee629 kernel.org Patch 
https://git.kernel.org/stable/c/6a2b724460cb67caed500c508c2ae5cf012e4db4 kernel.org Patch 
https://git.kernel.org/stable/c/6e5e3c87b7e6212f1d8414fc2e4d158b01e12025 kernel.org Patch 
https://git.kernel.org/stable/c/7edca70751b9bdb5b83eed53cde21eccf3c86147 kernel.org Patch 
https://git.kernel.org/stable/c/82baeb871e8f04906bc886273fdf0209e1754eb3 kernel.org Patch 
https://git.kernel.org/stable/c/faa6ea32797a1847790514ff0da1be1d09771580 kernel.org Patch 
https://git.kernel.org/stable/c/fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6 kernel.org Patch 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-908 Use of Uninitialized Resource cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-31427
NVD Published Date:
04/13/2026
NVD Last Modified:
05/20/2026
Source:
kernel.org