CVE-2026-27821Public exploit

Process abort via unbounded xmlHeaderEnd attribute copy

Published Feb 26, 2026 · Updated Feb 26, 2026

Stack buffer overflow in GPAC 26.02.0 and earlier allows attackers to crash the process by parsing a crafted NHML file. The NHML demuxer's nhmldmx_config_output function passes the xmlHeaderEnd attribute to strcpy, copying unbounded data into the 1,000-byte szXmlHeaderEnd stack buffer. Exploitation requires GPAC to parse the file; stack canaries bound the demonstrated consequence to a process abort, while builds without them expose instruction-pointer control.

CVSS severity7.8
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in GPAC 26.02.0 and earlier allows attackers to crash the process by parsing a crafted NHML file. The NHML demuxer's nhmldmx_config_output function passes the xmlHeaderEnd attribute to strcpy, copying unbounded data into the 1,000-byte szXmlHeaderEnd stack buffer. Exploitation requires GPAC to parse the file; stack canaries bound the demonstrated consequence to a process abort, while builds without them expose instruction-pointer control.

The record

CVE
CVE-2026-27821
Published
Feb 26, 2026
Updated
Feb 26, 2026
Vendor
GPAC Project
Product
GPAC
Classifications
CWE-121, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 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=<= 26.02.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

GPAC Project · GPACversion=<= 26.02.0

Published CVSS scores

7.7GitHub, Inc.CVSS: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
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1204.002Malicious File

Public exploit references

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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