Memory exhaustion in Starlet via unbounded buffering of chunked request bodies
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-770.
Summary
Starlet versions from 0.20 before 0.33 for Perl do not limit how much input the chunked request body decoder buffers. A chunk-size line without a CRLF grows the buffer for as long as the client keeps sending, and the read timeout restarts after every read. A remote attacker can exhaust a worker's memory with a single request.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
Starlet versions from 0.20 before 0.33 for Perl allow memory exhaustion via unbounded buffering when decoding chunked request bodies. The decoder adds each read to one buffer of unconsumed input. Nothing limits the length of a chunk-size line, so a line without a CRLF grows the buffer for as long as the client keeps sending, and the read timeout restarts after every read. The data of a large chunk is also held in the buffer until the whole chunk has arrived. A remote attacker can exhaust a worker's memory with a single request.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | Starlet | 0.20 to before 0.33 | 0.33 | Patch available | CNA |
- Starlet Vendor— Affected 0.20 to before 0.33 Fixed in 0.33 Patch available CNA
Remediation
Upgrade Starlet to version 0.33 or later.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Starlet Fixed in 0.33
Vendor assessments
Timeline
- 2026-10-30 Threatist record created from CVE-2026-116128
- 2026-10-30 Alias added: GHSA-jrjq-4h5w-6gv7
- 2026-10-31 Affected versions changed · Red Hat
- 2026-10-31 CVSS score added · Red Hat
- 2026-11-06 CVSS score added · CISA ADP
- 2026-11-06 CISA SSVC decision points changed
References
Sources
- CVE-2026-116128 · CVE Program
- CVE-2026-116128 · NVD
- FIRST EPSS
- GHSA-jrjq-4h5w-6gv7 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-116128 · Red Hat security data · CC BY 4.0
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