CVE-2026-88359

libfyaml 0.9.6 Stack Exhaustion Denial of Service

Published Sep 24, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
First Time appeared Pantoniou
Pantoniou libfyaml
Vendors & Products Pantoniou
Pantoniou libfyaml
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Title libfyaml 0.9.6 Stack Exhaustion Denial of Service
Type Values Removed Values Added
Weaknesses CWE-770
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
Description libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Sep 25, 2026, 4:18 PM
Reserved
Sep 10, 2026, 12:00 AM
Status
Deferred
Published
Sep 24, 2026, 2:18 PM
Modified
Sep 25, 2026, 5:17 PM