CVE catalog
CVE-2026-57076
YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck
- Severity
- High · CVSS 7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.17% · Oct 25, 2026
YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | libyaml-syck-perl | sid | 1.47-1 | fixed |
| Debian | libyaml-syck-perl | forky | 1.47-1 | fixed |
| Debian | libyaml-syck-perl | trixie | 1.34-2+deb13u3 | fixed |
| Debian | libyaml-syck-perl | trixie-security | 1.34-2+deb13u3 | fixed |
| Debian | libyaml-syck-perl | bookworm | 1.34-2+deb12u2 | vulnerable |
| Debian | libyaml-syck-perl | bookworm-security | 1.34-2+deb12u3 | fixed |
| Cpe | libyaml-syck-perl | Not reported | Not reported | vulnerable |
| Alpine | perl-yaml-syck | 3.24 | 1.47-r0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | libyaml-syck-perl | source | sid | 1.47-1 | not yet assigned | Not reported | [1142267] |
| Debian | libyaml-syck-perl | source | forky | 1.47-1 | not yet assigned | Not reported | [1142267] |
| Debian | libyaml-syck-perl | source | trixie | 1.34-2+deb13u3 | not yet assigned | Not reported | [1142267] |
| Debian | libyaml-syck-perl | source | bookworm | 1.34-2+deb12u3 | not yet assigned | Not reported | [1142267] |
| Alpine | perl-yaml-syck | apk | 3.24 | 1.47-r0 | Not reported | ALPINE-CVE-2026-57076 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libyaml-syck-perl]Affected
Details (4)
1.34-2+deb12u2· amd64 · bookwormAffected · Fixed:
1.34-2+deb12u3nvd · libyaml-syck-perl · debian · bookworm; nvd · libyaml-syck-perl · debian · 12
1.34-2+deb12u2· arm64 · bookwormAffected · Fixed:
1.34-2+deb12u3nvd · libyaml-syck-perl · debian · bookworm; nvd · libyaml-syck-perl · debian · 12
1.34-2+deb12u3· amd64 · bookworm-securityFixed · Fixed:
1.34-2+deb12u3nvd · libyaml-syck-perl · debian · bookworm; nvd · libyaml-syck-perl · debian · 12
1.34-2+deb12u3· arm64 · bookworm-securityFixed · Fixed:
1.34-2+deb12u3nvd · libyaml-syck-perl · debian · bookworm; nvd · libyaml-syck-perl · debian · 12
[Debian 13 (Trixie)]
- [libyaml-syck-perl]Affected
Details (5)
1.34-2+deb13u2· amd64 · trixieAffected · Fixed:
1.34-2+deb13u3nvd · libyaml-syck-perl · debian · 13
1.34-2+deb13u2· arm64 · trixieAffected · Fixed:
1.34-2+deb13u3nvd · libyaml-syck-perl · debian · 13
1.34-2+deb13u2· amd64 · trixie-security · Historical versionAffected · Fixed:
1.34-2+deb13u3nvd · libyaml-syck-perl · debian · 13
1.34-2+deb13u3· amd64 · trixie-securityFixed · Fixed:
1.34-2+deb13u3nvd · libyaml-syck-perl · debian · 13
1.34-2+deb13u3· arm64 · trixie-securityFixed · Fixed:
1.34-2+deb13u3nvd · libyaml-syck-perl · debian · 13
Observed:
References
- [http://www.openwall.com/lists/oss-security/2026/07/17/3]
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11299-1.json]
- [https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b.patch]
- [https://metacpan.org/release/TODDR/YAML-Syck-1.47/changes]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-57076]
- [https://osv.dev/vulnerability/ALPINE-CVE-2026-57076]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-57076]
- [https://security-tracker.debian.org/tracker/CVE-2026-57076]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-57076.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2508.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]