CVE-2026-31427

MEDIUM EPSS 1.8%
Published Apr 13, 20262mo ago · Modified Jun 17, 20262w ago
5.5 CVSS 3.1
Medium
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Published Apr 13, 2026 2mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
1.8% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-908

Affected Products 12

VendorProductVersionRange
linuxlinux_kernel*≥2.6.26  –  <5.10.253
linuxlinux_kernel*≥5.11  –  <5.15.203
linuxlinux_kernel*≥5.16  –  <6.1.168
linuxlinux_kernel*≥6.2  –  <6.6.131
linuxlinux_kernel*≥6.7  –  <6.12.80
linuxlinux_kernel*≥6.13  –  <6.18.21
linuxlinux_kernel*≥6.19  –  <6.19.11
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any

References 8

  • git.kernel.org https://git.kernel.org/stable/c/01f34a80ac23ae90b1909b94b4ed05343a62f646
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/52fdda318ef2362fc5936385bcb8b3d0328ee629
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6a2b724460cb67caed500c508c2ae5cf012e4db4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6e5e3c87b7e6212f1d8414fc2e4d158b01e12025
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/7edca70751b9bdb5b83eed53cde21eccf3c86147
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/82baeb871e8f04906bc886273fdf0209e1754eb3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/faa6ea32797a1847790514ff0da1be1d09771580
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/01f34a80ac23ae90b1909b94b4ed05343a62f646
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/52fdda318ef2362fc5936385bcb8b3d0328ee629
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6a2b724460cb67caed500c508c2ae5cf012e4db4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6e5e3c87b7e6212f1d8414fc2e4d158b01e12025
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/7edca70751b9bdb5b83eed53cde21eccf3c86147
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/82baeb871e8f04906bc886273fdf0209e1754eb3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/faa6ea32797a1847790514ff0da1be1d09771580
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6
    Patch