CVE-2026-115866: Starlet versions from 0.20 before 0.33 for Perl allow CPU exhaustion via regular expression
Affects starletSource GCVE Database
Not known to be exploited.
Data as of 5 Nov 2026, 12:35 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 30 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10starletpkg:deb/ubuntu/starlet?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSstarletpkg:deb/ubuntu/starlet?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSstarletpkg:deb/ubuntu/starlet?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSstarletpkg:deb/ubuntu/starlet?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSstarletpkg:deb/ubuntu/starlet?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu 18.04 LTSstarletpkg:deb/ubuntu/starlet?arch=source&distro=bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2026-115866 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-115866 (opens in a new tab)
- lists.security.metacpan.org/cve-announce/msg/44760437/ (opens in a new tab)
- github.com/kazuho/Starlet/commit/229ea56b3b50028e2a644156317e8d0e7cf68a1f.patch (opens in a new tab)
- metacpan.org/release/KAZUHO/Starlet-0.33/changes (opens in a new tab)