PJSIP's pjmedia-video has use-after-free in H264 packetizer when packetizing fragmented NAL
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA pjmedia-video (pjsip) Fixed in 2.17
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-26203
References
More Pjsip vulnerabilities
- TI-2022-08599 Potential out-of-bound read/write in PJSIP CVSS 3.1CRITICAL 9.8
- TI-2026-21009 PJSIP has a heap buffer overflow in ICE with long username CVSS 4.0HIGH 8.1
- TI-2022-18621 Buffer overflow in pjlib scanner and pjmedia CVSS 3.1CRITICAL 9.8
- TI-2026-29548 PJSIP: Stack buffer overflow in pjsip_auth_create_digest2() CVSS 4.0HIGH 8.1
- TI-2026-23213 PJSIP: Stack buffer overflow in Opus codec parser CVSS 4.0HIGH 8.7
- TI-2026-22993 PJSIP: Heap use-after-free in PJSIP presence subscription termination handler CVSS 4.0HIGH 8.7
Sources
- CVE-2026-26203 · CVE Program
- CVE-2026-26203 · NVD
- FIRST EPSS
- CVE-2026-26203 · Red Hat security data · CC BY 4.0
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