Cyber Resilience

CVE-2026-5435

Memory Safety in Gnu Glibc ≥ 2.2

Memory Safety
Published
28 April 2026
Modified
14 July 2026
CVSS Score v3.1 7.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS Score 0.0024 15th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-5435 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Gnu Glibc. Its CVSS base score is 7.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 15th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-5435 affects the GNU C Library (glibc) versions 2.2 and newer, specifically the deprecated functions ns_printrrf, ns_printrr, and fp_nquery. These functions fail to enforce the caller-supplied buffer length, leading to an out-of-bounds write when printing TSIG records. The vulnerability is classified under CWE-787 (Out-of-bounds Write) and carries a CVSS v3.1 base score of 7.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L), indicating high severity due to its network accessibility and ease of exploitation.

Unauthenticated remote attackers can exploit this vulnerability over the network with low attack complexity and no user interaction required. Exploitation triggers an out-of-bounds write, potentially allowing limited impacts on confidentiality, integrity, and availability, such as partial data disclosure, modification, or service disruption in affected glibc-dependent applications handling TSIG records.

Mitigation details are available in the referenced advisories, including the glibc-announce mailing list post at https://inbox.sourceware.org/libc-announce/7a655d55-276f-41fe-b550-feb3ebb2ce91@redhat.com/T/#u and the Sourceware Bugzilla entry at https://sourceware.org/bugzilla/show_bug.cgi?id=34033.

EU & UK References

Vulnerability Data

The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.2 and newer fail to enforce the caller-supplied buffer length, and can result in an out-of-bounds write when printing TSIG records.

CWE(s)
CWE-787

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 →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
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-2023-25139Same product: Gnu Glibc
CVE-2024-45780Same vendor: Gnu
CVE-2023-36273Same vendor: Gnu
CVE-2023-36272Same vendor: Gnu
CVE-2023-36271Same vendor: Gnu
CVE-2023-36274Same vendor: Gnu
CVE-2025-1125Same vendor: Gnu
CVE-2023-39128Same vendor: Gnu
CVE-2023-39130Same vendor: Gnu
CVE-2023-25222Same vendor: Gnu

Affected Assets

gnu
glibc
≥ 2.2

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation (including fuzzing and bounds checks) finds out-of-bounds write flaws before deployment.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.

SI-10 Information Input Validation partial match

Input validation can structurally reject or sanitize data that would otherwise trigger an out-of-bounds write.

SI-16 Memory Protection partial match

Memory-protection mechanisms limit the exploitability and blast radius of a successful out-of-bounds write.

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-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

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 and acceptance can detect and prevent out-of-bounds write defects.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify bounds-checking and safe memory handling.

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

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

A.8.28 Secure coding partial match
prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

A.8.32 Change management partial match
prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References