CVE-2026-15534

Publication date 9 August 2026

Last updated 8 September 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

5.7 · Medium

Score breakdown

Description

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

Status

Package Ubuntu Release Status
perl 26.04 LTS resolute
Fixed 5.40.1-7ubuntu0.2
24.04 LTS noble
Vulnerable
22.04 LTS jammy
Fixed 5.34.0-3ubuntu1.9
20.04 LTS focal
Fixed 5.30.0-9ubuntu0.5+esm4
18.04 LTS bionic
Fixed 5.26.1-6ubuntu0.7+esm4
16.04 LTS xenial
Fixed 5.22.1-9ubuntu0.9+esm4
14.04 LTS trusty
Fixed 5.18.2-2ubuntu1.7+esm9

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Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.7 · Medium

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

References

Related Ubuntu Security Notices (USN)

    • USN-8736-1
    • Perl vulnerabilities
    • 8 September 2026

Other references

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