Buffer overflow in Biojppm Rapidyaml
CVE-2026-120455
rapidyaml through 0.16.0 contains an out-of-bounds write vulnerability in ParseEngine::_add_annotation() that allows attackers to corrupt memory by supplying YAML with excess anchors or tags. Attackers can submit YAML with consecutive anchors or tags to overflow the fixed two-element annotation array in release builds, corrupting stack memory and crashing the process.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/biojppm/rapidyaml/issues/680 (issue-tracking)
- github.com/biojppm/rapidyaml/blob/v0.16.0/src/c4/yml/parse_engine.def.hpp (technical-description)
- github.com/biojppm/rapidyaml/blob/v0.16.0/src/c4/yml/parse_engine.def.hpp (technical-description)
- github.com/biojppm/rapidyaml/blob/v0.16.0/src/c4/yml/parse_engine.hpp (technical-description)
- github.com/biojppm/rapidyaml/releases/tag/v0.16.0 (release-notes)
- hackmd.io/@haindpwn/rapidyaml-parser-annotation-oob-write (technical-description)
- www.vulncheck.com/advisories/rapidyaml-through-0.16.0-out-of-bounds-write-via-p… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-120455?
- CVE-2026-120455 is a medium-severity vulnerability in Biojppm Rapidyaml, classified under Out-of-bounds Write. CVSS score: 6.1/10. Published 2026-11-02.
- How severe is CVE-2026-120455?
- Medium severity. CVSS v3 base score is 6.1 out of 10.