What is the CVSS score of CVE-2026-26203?

CVE-2026-26203 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H. EPSS exploitation probability: 0.0%.

Which versions of Pjsip are affected by CVE-2026-26203?

Organizations using PJSIP should be aware of notable risk from CVE-2026-26203, a use-after-free vulnerability rated CVSS 6.5. Exploitation could compromise the security of affected deployments.. A patch is available.

How to fix or mitigate CVE-2026-26203?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Pjsip CVE-2026-26203

MEDIUM

Use After Free (CWE-416)

2026-02-19 security-advisories@github.com

Use After Free Pjsip

6.5

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.5 MEDIUM

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:03 vuln.today

Patch released

Feb 20, 2026 - 20:12 nvd

Patch available

CVE Published

Feb 19, 2026 - 20:25 nvd

MEDIUM 6.5

DescriptionGitHub Advisory

PJSIP is a free and open source multimedia communication library. Versions prior to 2.17 have a critical heap buffer underflow vulnerability in PJSIP's H.264 packetizer. The bug occurs when processing malformed H.264 bitstreams without NAL unit start codes, where the packetizer performs unchecked pointer arithmetic that can read from memory located before the allocated buffer. Version 2.17 contains a patch for the issue.

AnalysisAI

PJSIP versions before 2.17 contain a use-after-free vulnerability in the H.264 packetizer that allows local attackers with user privileges to cause denial of service through malformed H.264 bitstreams lacking proper NAL unit markers. The flaw stems from inadequate pointer validation during packet processing, enabling out-of-bounds memory access that crashes the application. A patch is available in version 2.17 and later.

Technical ContextAI

Classified as CWE-416 (Use After Free). Affects Pjsip. PJSIP is a free and open source multimedia communication library. Versions prior to 2.17 have a critical heap buffer underflow vulnerability in PJSIP's H.264 packetizer. The bug occurs when processing malformed H.264 bitstreams without NAL unit start codes, where the packetizer performs unchecked pointer arithmetic that can read from memory located before the allocated buffer. Version 2.17 contains a patch for the issue.