CVE-2026-27821

GPAC NHML Demuxer (dmx_nhml.c) Vulnerable to Stack Buffer Overflow

7.7 High

GPAC is an open-source multimedia framework. In versions up to and including 26.02.0, a stack buffer overflow occurs during NHML file parsing in src/filters/dmx_nhml.c. The value of the xmlHeaderEnd XML attribute is copied from att->value into szXmlHeaderEnd[1000] using strcpy() without any length validation. If the input exceeds 1000 bytes, it overwrites beyond the stack buffer boundary. Commit 9bd7137fded2db40de61a2cf3045812c8741ec52 patches the issue.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

0.32%Up 0.3 points since Feb 26, 2026

What each source reports

CVE List Score used 7.7

GPAC NHML Demuxer (dmx_nhml.c) Vulnerable to Stack Buffer Overflow

Record: CVE-2026-27821
CVSS 4.0: 7.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
Weakness: CWE-121
Updated: 2026-11-02

EUVDEUVD-2026-8784 7.7

Record: EUVD-2026-8784
CVSS 4.0: 7.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
Updated: 2026-11-02

NVD 7.7

Record: CVE-2026-27821
CVSS 4.0: 7.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/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
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-121
Updated: 2026-11-02

OSV 7.7

GPAC NHML Demuxer (dmx_nhml.c) Vulnerable to Stack Buffer Overflow

Record: CVE-2026-27821
CVSS 4.0: 7.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
Weakness: CWE-121
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-27821 7.8

Record: DEBIAN-CVE-2026-27821
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-27821 7.7

Record: UBUNTU-CVE-2026-27821
CVSS 4.0: 7.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

Affected products

gpac

Affected packages

Affected packages
Package	Affected	Fixed
`gpac` Debian:11	All versions, plus listed versions 1.0.1+dfsg1-41.0.1+dfsg1-4+deb11u11.0.1+dfsg1-4+deb11u21.0.1+dfsg1-4+deb11u31.0.1+dfsg1-5 Show 8 moreShow less 2.0.0+dfsg1-12.0.0+dfsg1-22.0.0+dfsg1-42.2.1+dfsg1-12.2.1+dfsg1-22.2.1+dfsg1-32.2.1+dfsg1-3.12.2.1+dfsg1-3.1~exp1	None known
`gpac` Ubuntu:Pro:14.04:LTS	All versions, plus listed versions 0.5.0+svn4288~dfsg1-1ubuntu10.5.0+svn4288~dfsg1-40.5.0+svn4288~dfsg1-4ubuntu10.5.0+svn4288~dfsg1-4ubuntu1+esm10.5.0+svn4288~dfsg1-4ubuntu1+esm2	None known
`gpac` Ubuntu:Pro:16.04:LTS	All versions, plus listed versions 0.5.2-426-gc5ad4e4+dfsg5-1build10.5.2-426-gc5ad4e4+dfsg5-1ubuntu0.10.5.2-426-gc5ad4e4+dfsg5-1ubuntu0.1+esm2	None known
`gpac` Ubuntu:Pro:18.04:LTS	All versions, plus listed versions 0.5.2-426-gc5ad4e4+dfsg5-30.5.2-426-gc5ad4e4+dfsg5-3ubuntu0.10.5.2-426-gc5ad4e4+dfsg5-3ubuntu0.1+esm1	None known
`gpac` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 0.5.2-426-gc5ad4e4+dfsg5-4ubuntu10.5.2-426-gc5ad4e4+dfsg5-50.5.2-426-gc5ad4e4+dfsg5-5ubuntu0.1~esm2	None known
`gpac` Ubuntu:Pro:22.04:LTS	All versions, plus listed versions 1.0.1+dfsg1-41.0.1+dfsg1-52.0.0+dfsg1-22.0.0+dfsg1-2ubuntu0.1~esm2	None known
`gpac` Ubuntu:Pro:24.04:LTS	All versions, plus listed versions 2.2.1+dfsg1-32.2.1+dfsg1-3.12.2.1+dfsg1-3.1build12.2.1+dfsg1-3.1build22.2.1+dfsg1-3.1ubuntu0.1~esm2	None known

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-27821 is a high vulnerability (CVSS 7.7) in Gpac, published February 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.32%, the 25th percentile. No source names a fixed version.