CVE-2026-31427
What it 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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 5.5 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-908
- Record status
- Modified
Affected
- Linux Kernel < 5.10.253
- Linux Kernel < 5.15.203
- Linux Kernel < 6.1.168
- Linux Kernel < 6.6.131
- Linux Kernel < 6.12.80
- Linux Kernel < 6.18.21
- Linux Kernel < 6.19.11
- Linux Kernel 7.0
Attack profile CVSS 3.1 · 5.5
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-31427.md and follow it. Check whether this project is affected by CVE-2026-31427. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/01f34a80ac23ae90b1909b94b4ed05343a62f646
- https://git.kernel.org/stable/c/52fdda318ef2362fc5936385bcb8b3d0328ee629
- https://git.kernel.org/stable/c/6a2b724460cb67caed500c508c2ae5cf012e4db4
- https://git.kernel.org/stable/c/6e5e3c87b7e6212f1d8414fc2e4d158b01e12025
- https://git.kernel.org/stable/c/7edca70751b9bdb5b83eed53cde21eccf3c86147
- https://git.kernel.org/stable/c/82baeb871e8f04906bc886273fdf0209e1754eb3
- https://git.kernel.org/stable/c/faa6ea32797a1847790514ff0da1be1d09771580
- https://git.kernel.org/stable/c/fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6
References
- https://git.kernel.org/stable/c/01f34a80ac23ae90b1909b94b4ed05343a62f646
- https://git.kernel.org/stable/c/52fdda318ef2362fc5936385bcb8b3d0328ee629
- https://git.kernel.org/stable/c/6a2b724460cb67caed500c508c2ae5cf012e4db4
- https://git.kernel.org/stable/c/6e5e3c87b7e6212f1d8414fc2e4d158b01e12025
- https://git.kernel.org/stable/c/7edca70751b9bdb5b83eed53cde21eccf3c86147
- https://git.kernel.org/stable/c/82baeb871e8f04906bc886273fdf0209e1754eb3
- https://git.kernel.org/stable/c/faa6ea32797a1847790514ff0da1be1d09771580
- https://git.kernel.org/stable/c/fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html