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CVE-2026-88359

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 functio

n/a n/a
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CVSS
6.5Medium
ExploitationPublic exploit codeCISA's assessment says proof of concept code is public, assessed 25 Sep 2026. Not in the KEV catalogCISA via CVE List
Exploit odds (EPSS)0.25%Chance of exploitation activity in the next 30 days, higher than 15% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published24 Sep 2026Updated 25 Sep 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

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.

Text from CVE List

Affected versions 1

  • n/aaffected: n/aCVE List

References 3