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CVE-2026-5089· NVD / CVE Program· CNA CPANSec

YAML::Syck versions before 1.38 for Perl has an out-of-bounds read

Noroxi assessment

Priority: Monitor (action score 29/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.42% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: libyaml-syck-perl (Debian:12) 1.34-2+deb12u3; libyaml-syck-perl (Debian:13) 1.34-2+deb13u3; libyaml-syck-perl (Debian:14) 1.36-3.

Low priority for now. Upgrade to libyaml-syck-perl (Debian:12) 1.34-2+deb12u3; libyaml-syck-perl (Debian:13) 1.34-2+deb13u3; libyaml-syck-perl (Debian:14) 1.36-3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

YAML::Syck versions before 1.38 for Perl has an out-of-bounds read. The base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer: while ( colon >= ptr && *colon != ':' ) { colon--; } if ( *colon == ':' ) *colon = '\0'; // colon may be ptr-1 here When no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent *colon dereference reads one byte before the allocated buffer.

HighCVSS 7.3 · v3.1—No exploit Fix available
Published
May 12, 2026
Updated
Jun 17, 2026
EPSS
0.4% · 35th percentile

Report tools

JSON

Action score

29

Monitor

Low priority for now.

CVSS
29 / 40 · 7.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (CPANSec). Independent of NVD's CPE analysis and usually ahead of it.

  • TODDR YAML::Syck

    • before 1.38affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12libyaml-syck-perlbefore 1.34-2+deb12u31.34-2+deb12u3
Debian:13libyaml-syck-perlbefore 1.34-2+deb13u31.34-2+deb13u3
Debian:14libyaml-syck-perlbefore 1.36-31.36-3
openSUSE:Leap 16.0perl-YAML-Syckbefore 1.450.0-bp160.2.11.450.0-bp160.2.1
openSUSE:Tumbleweedperl-YAML-Syckbefore 1.450.0-4.11.450.0-4.1

Same product

toddr: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-57075YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syck_base64dec
    36Monitor
  • CVE-2026-57076YAML::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
    31Monitor
  • CVE-2026-57077YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-11683Oct 16, 2025 · YAML::Syck versions before 1.36 for Perl has missing Null-Terminators which causes Out-of-Bounds Read and potential Information Disclosure
    26Monitor
  • Later →CVE-2026-13713Jul 16, 2026 · YAML::Syck versions before 1.47 for Perl allow a use-after-free and double-free via an anchor node freed while still on the parser value stack
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:libyaml-syck-perl1.34-2+deb12u3 · Debian:12Package registry (OSV)
opensuse:perl-YAML-Syck1.450.0-4.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
low · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
Low

Weakness class (CWE)

CWE-124 · Buffer Underwrite ('Buffer Underflow')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records