Cyber Resilience

CVE-2026-12549

Redhat Enterprise Linux 10.0 … 9.0

Public PoC
Published
22 June 2026
Modified
08 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 4.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
EPSS Score 0.0041 34th percentile
Risk Priority 39 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-12549 is a medium-severity Buffer Access with Incorrect Length Value (CWE-805) vulnerability in Redhat Enterprise Linux. Its CVSS base score is 4.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 34th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

The fix for CVE-2026-2443 was regressed by a subsequent rework commit that replaced specific overflow checks with a general signed comparison. When a client sends a Range request with a suffix length exceeding the content size, the resulting negative start…

more

value is not properly clamped, leading to malformed HTTP 206 responses and log flooding.

CWE(s)
CWE-805

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-4271Same product: Gnome Libsoup
CVE-2026-2436Same product: Gnome Libsoup
CVE-2026-2443Same product: Gnome Libsoup
CVE-2026-12548Same product: Gnome Libsoup
CVE-2026-1767Same product: Redhat Enterprise Linux
CVE-2026-1766Same product: Redhat Enterprise Linux
CVE-2026-3632Same product: Gnome Libsoup
CVE-2026-2708Same product: Gnome Libsoup
CVE-2026-1801Same product: Gnome Libsoup
CVE-2026-1536Same product: Gnome Libsoup

Affected Assets

redhat
enterprise linux
10.0, 6.0, 7.0, 8.0, 9.0
gnome
libsoup
all versions

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation (including fuzzing and static analysis) directly finds incorrect length values used in sequential buffer accesses.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles require explicit bounds checking and correct length calculations when performing buffer operations.

SI-10 Information Input Validation partial match

Input validation rejects or corrects malformed length values supplied from external sources before they reach buffer operations.

SI-16 Memory Protection partial match

Memory protection mechanisms limit the blast radius when an incorrect length value causes an out-of-bounds access.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent incorrect-length buffer operations via safe APIs, reviews, and testing.

ID.RA-01 partial match
prevents

Vulnerability identification can discover buffer-length flaws but does not prevent their introduction.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect out-of-bounds accesses, but does not guarantee prevention.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates buffer-safety practices that directly prevent incorrect length values.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify buffer-size validation, but do not prescribe implementation details.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage bounds-checked APIs, yet leave concrete coding decisions to developers.

A.8.28 Secure coding partial match
prevents

Secure coding explicitly requires correct buffer-length handling, eliminating CWE-805 when followed.

References