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Fencer Vulns
critical 9.1

CVE-2026-59145 json

Data::Intern::Shared versions before 0.02 for Perl allow an out-of-bounds read via unvalidated slot, reverse and arena indices in si_idx_find

published 2026-07-21 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-46366

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

Data::Intern::Shared versions before 0.02 for Perl allow an out-of-bounds read via unvalidated slot, reverse and arena indices in si_idx_find.

The attach-time validator si_validate_header is thorough about the header and layout (magic, version, section offsets, total_size, count and arena_used) but does not validate the three arrays it then trusts. Every lookup in si_idx_find walks a triple indirection read straight from the mmap'd segment, arena[reverse[slots[i].id]], with no bound on slots[i].id against count, on the reverse[id] arena offset against arena_used, or on the arena record's length prefix.

A local peer that can write the backing file can leave the header valid while poisoning a slot id, a reverse offset or an arena length prefix, so an id_of, intern or string lookup dereferences the chain out of bounds; because string() returns a file-controlled length of bytes from the arena, adjacent process memory can be disclosed.

Patch / fix

  • EGOR Data::Intern::Shared 0.02

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected products

  • EGOR Data::Intern::Shared

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.