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Fencer Vulns
medium 6.5

CVE-2026-26203 json

PJSIP's pjmedia-video has use-after-free in H264 packetizer when packetizing fragmented NAL

published 2026-02-19 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-7974

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

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.

Patch / fix

  • pjsip pjsip 2.17
  • asterisk Debian 14 1:22.10.0+dfsg+~cs6.17.60671434-1

debian advisories DEBIAN-CVE-2026-26203

  • pjproject Alpine 3.24 2.17-r0

alpine advisories ALPINE-CVE-2026-26203

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-26203 updated cvss 5.3

pjsip: PJSIP: Denial of Service via malformed H.264 bitstream processing

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.1 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:L
CNA 4.0 5.1 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 6.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Affected products

  • pjsip pjmedia-video

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.