CVE-2025-8879Network attack vector

Heap corruption via mis-sized libaom SAD buffer

Published Aug 13, 2025 · Updated Feb 26, 2026

Heap buffer overflow in libaom in Google Chrome before 139.0.7258.127 allows remote attackers to corrupt heap memory via crafted media interactions. In av1/encoder/ratectrl.c, incorrect full-resolution row and column values underallocate src_sad_blk_64x64 before blockwise SAD access. Triggering the flaw requires user interaction with real-time AV1 encoding that switches from two to three spatial layers and then uses a lower-resolution top layer, allowing out-of-bounds heap access in the browser process.

CVSS severity8.8
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in libaom in Google Chrome before 139.0.7258.127 allows remote attackers to corrupt heap memory via crafted media interactions. In av1/encoder/ratectrl.c, incorrect full-resolution row and column values underallocate src_sad_blk_64x64 before blockwise SAD access. Triggering the flaw requires user interaction with real-time AV1 encoding that switches from two to three spatial layers and then uses a lower-resolution top layer, allowing out-of-bounds heap access in the browser process.

The record

CVE
CVE-2025-8879
Published
Aug 13, 2025
Updated
Feb 26, 2026
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-122, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2025CVE 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=139.0.7258.127 <139.0.7258.127

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=139.0.7258.127 <139.0.7258.127

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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