CVE Explorer
CVE-2026-40561
Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence.
Starlet incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence.
An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"collectionURL":"https://cpan.org/modules","defaultStatus":"unaffected","packageName":"Starlet","product":"Starlet","programFiles":["lib/Starlet/Server.pm"],"programRoutines":[{"name":"Starlet::Server::handle_connection"}],"repo":"https://github.com/kazuho/Starlet","vendor":"KAZUHO","versions":[{"lessThanOrEqual":"0.31","status":"affected","version":"0","versionType":"custom"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:636ded54b01759430f7cf92e15c865c29cefccc7968aa52872f3690f37d999a2 · sha256:52b767d5ca38ccb8… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:636ded54b01759430f7cf92e15c865c29cefccc7968aa52872f3690f37d999a2 · sha256:52b767d5ca38ccb8… · /containers/adp/1/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-444","description":"CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:636ded54b01759430f7cf92e15c865c29cefccc7968aa52872f3690f37d999a2 · sha256:52b767d5ca38ccb8… · /containers/cna/problemTypes/0/descriptions/0
Source references
4 source assertions{"url":"http://www.openwall.com/lists/oss-security/2026/05/03/1"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:636ded54b01759430f7cf92e15c865c29cefccc7968aa52872f3690f37d999a2 · sha256:52b767d5ca38ccb8… · /containers/adp/0/references/0
{"url":"https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:636ded54b01759430f7cf92e15c865c29cefccc7968aa52872f3690f37d999a2 · sha256:52b767d5ca38ccb8… · /containers/cna/references/0
{"tags":["patch"],"url":"https://github.com/kazuho/Starlet/commit/a7d5dfd1862aafa43e5eaca0fdb6acf4cc15b2d0.patch"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:636ded54b01759430f7cf92e15c865c29cefccc7968aa52872f3690f37d999a2 · sha256:52b767d5ca38ccb8… · /containers/cna/references/1
{"tags":["release-notes"],"url":"https://metacpan.org/release/KAZUHO/Starlet-0.32/changes"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:636ded54b01759430f7cf92e15c865c29cefccc7968aa52872f3690f37d999a2 · sha256:52b767d5ca38ccb8… · /containers/cna/references/2
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.