Linux Kernel up to 6.19.10 nf_conntrack_sip process_sdp uninitialized pointer

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CTI Interest Score
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5.4$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10 and classified as critical. This impacts the function process_sdp of the component nf_conntrack_sip. This manipulation causes uninitialized pointer. This vulnerability is tracked as CVE-2026-31427. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10. Affected by this vulnerability is the function process_sdp of the component nf_conntrack_sip. The manipulation with an unknown input leads to a uninitialized pointer vulnerability. The CWE definition for the vulnerability is CWE-824. The product accesses or uses a pointer that has not been initialized. The impact remains unknown. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-31427 since 03/09/2026. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/18/2026).

The vulnerability scanner Nessus provides a plugin with the ID 313522 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1681)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.168, 6.6.131, 6.12.80, 6.18.21 or 6.19.11 eliminates this vulnerability. Applying the patch 6e5e3c87b7e6212f1d8414fc2e4d158b01e12025/fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6/7edca70751b9bdb5b83eed53cde21eccf3c86147/01f34a80ac23ae90b1909b94b4ed05343a62f646/52fdda318ef2362fc5936385bcb8b3d0328ee629/6a2b724460cb67caed500c508c2ae5cf012e4db4 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (313522), EUVD (EUVD-2026-21954) and CERT Bund (WID-SEC-2026-1088). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Microsoft Azure Linux
  • Open Source Linux Kernel

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Uninitialized pointer
CWE: CWE-824 / CWE-908
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 313522
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1681)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.168/6.6.131/6.12.80/6.18.21/6.19.11
Patch: 6e5e3c87b7e6212f1d8414fc2e4d158b01e12025/fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6/7edca70751b9bdb5b83eed53cde21eccf3c86147/01f34a80ac23ae90b1909b94b4ed05343a62f646/52fdda318ef2362fc5936385bcb8b3d0328ee629/6a2b724460cb67caed500c508c2ae5cf012e4db4

Timelineinfo

03/09/2026 CVE reserved
04/13/2026 +34 days Advisory disclosed
04/13/2026 +0 days VulDB entry created
06/18/2026 +66 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31427 (🔒)
GCVE (CVE): GCVE-0-2026-31427
GCVE (VulDB): GCVE-100-357157
EUVD: 🔒
CERT Bund: WID-SEC-2026-1088 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/13/2026 16:06
Updated: 06/18/2026 16:09
Changes: 04/13/2026 16:06 (59), 04/13/2026 17:58 (1), 05/10/2026 05:45 (2), 05/21/2026 01:09 (10), 06/18/2026 16:09 (7)
Complete: 🔍
Cache ID: 216::103

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