Red Hat Enterprise Linux 10.0 Extended Update…: Heap-based Buffer Overflow
CVE-2026-56208 is a high-severity heap-based buffer overflow vulnerability in Red Hat Enterprise Linux 10.0 Extended Update Support from Red Hat, with a CVSS 3.1 base score of 7.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. There is no confirmed exploitation so far. EPSS estimates a 0.45% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Red Hat Enterprise Linux 10.0 Extended Update Support you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 1 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H. Scored by CNA (redhat.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.6 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.6 | High | CNA |
Official description
A heap buffer overflow vulnerability was found in libaom, the reference AV1 codec implementation. A flaw in the AV1 encoder's Look-Ahead Processing (LAP) mode causes the first-pass stats ring buffer wrap-around guard to be bypassed when g_lag_in_frames is set to 1 or higher. This results in a 232-byte out-of-bounds write on every encoded frame after the second, corrupting adjacent heap objects. An attacker who can influence encoder configuration in a transcoding service or WebRTC session could exploit this to cause a denial of service (process crash) or potentially achieve code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Heap-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the heap.
How developers prevent this class of flaw
- Pre-design: Use a language or compiler that performs automatic bounds checking.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
- access.redhat.com/errata/RHSA-2026:30814
- access.redhat.com/errata/RHSA-2026:42875
- access.redhat.com/errata/RHSA-2026:47104
- access.redhat.com/errata/RHSA-2026:47105
- access.redhat.com/errata/RHSA-2026:51100
- access.redhat.com/errata/RHSA-2026:51146
- access.redhat.com/errata/RHSA-2026:54180
- access.redhat.com/errata/RHSA-2026:54181
- access.redhat.com/errata/RHSA-2026:54182
- access.redhat.com/errata/RHSA-2026:54185
- access.redhat.com/errata/RHSA-2026:54248
- access.redhat.com/errata/RHSA-2026:54249
- access.redhat.com/errata/RHSA-2026:54259
- access.redhat.com/errata/RHSA-2026:54339
- access.redhat.com/errata/RHSA-2026:60520
Other vulnerabilities in Red Hat Enterprise Linux 10.0 Extended Update Support
- 9.8 Critical severity
- 8.6 High severity
- 8.6 High severity
- 8.2 High severity
- 8.6 High severity
- 8.6 High severity
Recent Heap-based Buffer Overflow vulnerabilities
- 7.4 High severity
- 8.1 High severity
- 8.8 High severity
- 8.8 High severity
- 7.8 High severity
- 8.8 High severity
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