Description
Starlet versions from 0.20 before 0.33 for Perl allow CPU exhaustion via regular expression backtracking when decoding chunked request bodies.

A chunk-size line is matched as a run of hex digits, then .* and a CRLF. A run followed by a bare LF and then a CRLF can never match, and the engine retries the match once for each digit, so the time taken grows with the square of the run length. Nothing limits the length of the run, which can span several reads.

A remote attacker can occupy a worker for about a minute of CPU time with one 128 KiB request, before the application is called.
Published: 2026-10-30
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

Upgrade to Starlet 0.33 or later.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Wed, 04 Nov 2026 00:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Important


Fri, 30 Oct 2026 15:00:00 +0000

Type Values Removed Values Added
First Time appeared Kazuho
Kazuho starlet
Vendors & Products Kazuho
Kazuho starlet

Fri, 30 Oct 2026 13:00:00 +0000

Type Values Removed Values Added
Description Starlet versions from 0.20 before 0.33 for Perl allow CPU exhaustion via regular expression backtracking when decoding chunked request bodies. A chunk-size line is matched as a run of hex digits, then .* and a CRLF. A run followed by a bare LF and then a CRLF can never match, and the engine retries the match once for each digit, so the time taken grows with the square of the run length. Nothing limits the length of the run, which can span several reads. A remote attacker can occupy a worker for about a minute of CPU time with one 128 KiB request, before the application is called.
Title Starlet versions from 0.20 before 0.33 for Perl allow CPU exhaustion via regular expression backtracking when decoding chunked request bodies
Weaknesses CWE-1333
References

cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-10-30T12:45:39.814Z

Reserved: 2026-10-23T17:41:34.521Z

Link: CVE-2026-115866

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-30T13:18:31.070

Modified: 2026-10-30T17:13:54.187

Link: CVE-2026-115866

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-30T12:45:39Z

Links: CVE-2026-115866 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-11-04T07:30:10Z

Weaknesses