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TI-2025-19961 Aliases CVE-2025-27091

OpenH264 Decoding Functions Heap Overflow Vulnerability

Priority MEDIUM 46CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-122 and the CVSS impact.

Summary

OpenH264 is a free license codec library which supports H.264 encoding and decoding. A vulnerability in the decoding functions of OpenH264 codec library could allow a remote, unauthenticated attacker to trigger a heap overflow. This vulnerability is due to a race condition between a Sequence Parameter Set (SPS) memory allocation and a subsequent non Instantaneous Decoder Refresh (non-IDR) Network Abstraction Layer (NAL) unit memory usage. An attacker could exploit this vulnerability by crafting a malicious bitstream and tricking a victim user into processing an arbitrary video containing the malicious bistream. An exploit could allow the attacker to cause an unexpected crash in the victim's user decoding client and, possibly, perform arbitrary commands on the victim's host by abusing the heap overflow. This vulnerability affects OpenH264 2.5.0 and earlier releases. Both Scalable Video Coding (SVC) mode and Advanced Video Coding (AVC) mode are affected by this vulnerability. OpenH264 software releases 2.6.0 and later contained the fix for this vulnerability. Users are advised to upgrade. There are no known workarounds for this vulnerability. ### For more information If you have any questions or comments about this advisory: * [Open an issue in cisco/openh264](https://github.com/cisco/openh264/issues) * Email Cisco Open Source Security ([[email protected]](mailto:[email protected])) and Cisco PSIRT ([[email protected]](mailto:[email protected])) ### Credits: * **Research:** Octavian Guzu and Andrew Calvano of Meta * **Fix ideation:** Philipp Hancke and Shyam Sadhwani of Meta * **Fix implementation:** Benzheng Zhang (@BenzhengZhang) * **Release engineering:** Benzheng Zhang (@BenzhengZhang)

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00687 52nd percentileScored 2026-11-07
Fix Fixed openh264 (cisco): 2.6.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Ciscoopenh264before 2.6.02.6.0Patch availableCNA
  • openh264 VendorCisco Affected before 2.6.0 Fixed in 2.6.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:cisco:openh264:*:*:*:*:*:*:*:*before 2.5.1VulnerableCisco
  • cpe:2.3:a:cisco:openh264:*:*:*:*:*:*:*:* Versions before 2.5.1 Vulnerable ·Cisco

Remediation

  • Fix · CNA openh264 (cisco) Fixed in 2.6.0

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-27091

References

  • TI-2014-06650 Buffer overflow in decode.cpp in Cisco OpenH264 1.2.0 and earlier allows remote attackers… CVSS 2.0HIGH 7.5
  • TI-2014-06651 Use-after-free vulnerability in decode_slice.cpp in Cisco OpenH264 1.2.0 and earlier… CVSS 2.0HIGH 7.5

Sources