CVE-2026-31427

SIP session corruption via uninitialized RTP address

Published Apr 13, 2026 · Updated Apr 13, 2026

Use of an uninitialized value in affected Linux Kernel releases allows local users to corrupt rewritten SIP SDP session addresses. process_sdp passes an unassigned stack rtp_addr to the NAT sdp_session hook when no recognized, active media description supplies an address, and nf_nat_sdp_session formats that stale value into the session owner and connection lines. Reachability requires the nf_conntrack_sip and NAT helpers to process an SDP body with no usable media address; initialized stacks typically substitute 0.0.0.0, while other builds can insert stale stack data.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use of an uninitialized value in affected Linux Kernel releases allows local users to corrupt rewritten SIP SDP session addresses. process_sdp passes an unassigned stack rtp_addr to the NAT sdp_session hook when no recognized, active media description supplies an address, and nf_nat_sdp_session formats that stale value into the session owner and connection lines. Reachability requires the nf_conntrack_sip and NAT helpers to process an SDP body with no usable media address; initialized stacks typically substitute 0.0.0.0, while other builds can insert stale stack data.

The record

CVE
CVE-2026-31427
Published
Apr 13, 2026
Updated
Apr 13, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-908, T1565.002
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.26
  2. Affected versionversion=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <01f34a80ac23ae90b1909b94b4ed05343a62f646
  3. Affected versionversion=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <52fdda318ef2362fc5936385bcb8b3d0328ee629
  4. Affected versionversion=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <6a2b724460cb67caed500c508c2ae5cf012e4db4
  5. Affected versionversion=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <6e5e3c87b7e6212f1d8414fc2e4d158b01e12025
  6. Affected versionversion=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <7edca70751b9bdb5b83eed53cde21eccf3c86147
  7. Affected versionversion=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.26; version=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <01f34a80ac23ae90b1909b94b4ed05343a62f646; version=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <52fdda318ef2362fc5936385bcb8b3d0328ee629; version=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <6a2b724460cb67caed500c508c2ae5cf012e4db4; version=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <6e5e3c87b7e6212f1d8414fc2e4d158b01e12025; version=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <7edca70751b9bdb5b83eed53cde21eccf3c86147; version=4ab9e64e5e3c0516577818804aaf13a630d67bc9 <fe463e76c9b4b0b43b5ee8961b4c500231f1a3f6

Published CVSS scores

5.6Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
5.8OracleCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1565.002Transmitted Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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