IM
IronMonkey Threat Research

CVE-2026-31427 MEDIUM

Published: 2026-04-13 | Last Modified: 2026-07-14 | Status: Modified

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 Metrics

Base Score: 5.5 (MEDIUM)

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack VectorLOCAL
Attack ComplexityLOW
Privileges RequiredLOW
User InteractionNONE
ScopeUNCHANGED
Confidentiality ImpactNONE
Integrity ImpactNONE
Availability ImpactHIGH

Source: [email protected]

Type: Primary

Exploitability Score: 1.8

Impact Score: 3.6

Weaknesses

Source Type Description
[email protected] Primary
en CWE-908

Affected Products

Vendor Product Version Update Type
linux linux_kernel * <built-in method update of dict object at 0x702bde534100> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bde167080> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdd564480> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bde5358c0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bde535700> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bde535ec0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdd5662c0> Operating System
linux linux_kernel 7.0 <built-in method update of dict object at 0x702bde165680> Operating System
linux linux_kernel 7.0 <built-in method update of dict object at 0x702bde167b00> Operating System
linux linux_kernel 7.0 <built-in method update of dict object at 0x702bde537800> Operating System
linux linux_kernel 7.0 <built-in method update of dict object at 0x702b80ad9600> Operating System
linux linux_kernel 7.0 <built-in method update of dict object at 0x702bde164440> Operating System

Affected Configurations

Operator: OR

Vulnerable CPE
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*

References

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