{"id":"CVE-2026-88359","title":"libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format()","summary":"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…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","cwe":["CWE-770"],"vendor":"Red Hat","published":"2026-09-24","updated":"2026-09-25","sourceUpdated":"2026-09-25T17:17:17.490","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-88359","references":[{"url":"https://github.com/pantoniou/libfyaml/commit/20502068902d58c076da873117985798df2c7e74","label":"cve@mitre.org"},{"url":"https://github.com/pantoniou/libfyaml/commit/93741a7c9331da9da65ef7a25f2d7d6a817a1c29","label":"cve@mitre.org"},{"url":"https://github.com/pantoniou/libfyaml/issues/315","label":"cve@mitre.org"},{"url":"https://github.com/pantoniou/libfyaml/issues/315","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88359.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-88359"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-88359"}],"tags":["nvd","cve.org","csaf","vex","red-hat","exploit-available"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-25T16:18:24.616054Z"},"scores":{"nvd":6.5,"vendor":6.2,"adp":6.5},"ingestedAt":"2026-09-24T14:44:21.326Z","epss":0.00296,"epssPercentile":0.22134,"slug":"CVE-2026-88359","body":"## Overview\n\nlibfyaml 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88359.json)","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":211103,"id":"CVE-2026-88359","ts":1790360095348,"field":"cvss","old":"6.2","new":"6.5"},{"seq":211085,"id":"CVE-2026-88359","ts":1790356448334,"field":"exploit_available","old":"false","new":"true"},{"seq":210675,"id":"CVE-2026-88359","ts":1790322169111,"field":"cvss","old":null,"new":"6.2"},{"seq":210674,"id":"CVE-2026-88359","ts":1790322169111,"field":"severity","old":"none","new":"medium"}]}