Cyber Resilience

CVE-2025-6499

LowPublic PoC

Published: 23 June 2025

Published
23 June 2025
Modified
29 April 2026
KEV Added
Patch
CVSS Score v4 1.9 CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0013 32.0th percentile
Risk Priority 4 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-6499 is a low-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Vstakhov Libucl. Its CVSS base score is 1.9 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 32.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

A vulnerability classified as problematic was found in vstakhov libucl up to 0.9.2. Affected by this vulnerability is the function ucl_parse_multiline_string of the file src/ucl_parser.c. The manipulation leads to heap-based buffer overflow. The attack needs to be approached locally. The…

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exploit has been disclosed to the public and may be used.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

Local heap-based buffer overflow enables denial of service via application crash (T1499.004) and potentially privilege escalation through exploitation in elevated processes (T1068).

Affected Assets

vstakhov
libucl
≤ 0.9.2

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-119 CWE-787

Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.

addresses: CWE-119

Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.

addresses: CWE-119

Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.

addresses: CWE-119

Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.

References