CVE-2026-57075
CRITICALYAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syck_base64dec
Description
YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syck_base64dec.
The base64 decoder in the bundled libsyck indexes the 256-entry static table b64_xtable with a signed char, so any !!binary byte >= 0x80 sign-extends to a negative index and reads before the table. The decoder receives the raw bytes of any !!binary node, a standard YAML type not gated by $LoadBlessed or $LoadCode, so it is reached on the default Load path.
Any caller that runs Load or LoadFile on an untrusted document containing a !!binary scalar with a high-bit byte triggers the read, and the value read can surface in the decoded result.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-57075 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-57075 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-57075. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-57075 in your dependencies?
O3 detects CVE-2026-57075 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.