CVE-2026-0708

Libucl: libucl: denial of service via embedded null byte in ucl input

Published Mar 17, 2026 CVSS 3.1 · 8.3 High EPSS < 1% KEV · Not listed
Description
A flaw was found in libucl. A remote attacker could exploit this by providing a specially crafted Universal Configuration Language (UCL) input that contains a key with an embedded null byte. This can cause a segmentation fault (SEGV fault) in the `ucl_object_emit` function when parsing and emitting the object, leading to a Denial of Service (DoS) for the affected system.

Remediation

Vendor Workaround

To mitigate this issue, applications utilizing `libucl` should avoid processing untrusted input that contains keys with embedded null bytes, especially when operating in `UCL_PARSER_ZEROCOPY` mode. Restricting input to trusted sources can reduce exposure.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Vstakhov
Vstakhov libucl
CPEs cpe:2.3:a:vstakhov:libucl:*:*:*:*:*:*:*:*
Vendors & Products Vstakhov
Vstakhov libucl
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Libucl
Libucl libucl
Vendors & Products Libucl
Libucl libucl
Type Values Removed Values Added
Description A flaw was found in libucl. A remote attacker could exploit this by providing a specially crafted Universal Configuration Language (UCL) input that contains a key with an embedded null byte. This can cause a segmentation fault (SEGV fault) in the `ucl_object_emit` function when parsing and emitting the object, leading to a Denial of Service (DoS) for the affected system.
Title Libucl: libucl: denial of service via embedded null byte in ucl input
Weaknesses CWE-125
References
Metrics cvssV3_1

{'score': 8.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
fedora
Published
Updated
Mar 17, 2026, 1:26 PM
Reserved
Jan 8, 2026, 3:31 AM
Status
Analyzed
Published
Mar 17, 2026, 4:16 AM
Modified
Jun 17, 2026, 10:11 AM