CVE-2025-6499: A vulnerability classified as problematic was found in vstakhov libucl up to 0.9.2

Q: How do I fix CVE-2025-6499?

libucl: upgrade to newer than 0.9.2. Exact commands for each OS are on this page.

Q: Is CVE-2025-6499 being exploited?

CVE-2025-6499 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-6499 affect?

CVE-2025-6499 affects libucl. Severity is low (CVSS 3.3). 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

Q: How urgent is CVE-2025-6499?

Priority 21/100. Public exploit reference

Routine

LOW 3.3UPGRADE

CVE-2025-6499 is a low-severity flaw (CVSS 3.3) affecting libucl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-119, CWE-122, CWE-787
Published	2025-06-23
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: vstakhov

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-06-23 03:15 UTCPublished CVE record published
2026-06-17 10:02 UTCUpdated Record last modified

vstakhov libucl UPGRADE

Affected: <= 0.9.2

Fixed in: newer than 0.9.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libucl || rpm -q libucl || libucl --version

2. UPGRADE to newer than 0.9.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libucl

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libucl

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-6499?

libucl: upgrade to newer than 0.9.2. Exact commands for each OS are on this page.

Is CVE-2025-6499 being exploited?

CVE-2025-6499 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-6499 affect?

CVE-2025-6499 affects libucl. Severity is low (CVSS 3.3). 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

How urgent is CVE-2025-6499?

Priority 21/100. Public exploit reference

Related CVEs

CVE-2026-0708 HIGH 8.3 UPGRADE A flaw was found in libucl

References

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