CVE-2025-12642: medium-severity vulnerability in lighttpd
HTTP Header Smuggling via Trailer Merge
Published
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.9epss 0.4%
lighttpd1.4.80 incorrectly merged trailer fields into headers after http request parsing. This behavior can be exploited to conduct HTTP Header Smuggling attacks.
Successful exploitation may allow an attacker to:
* Bypass access control rules
* Inject unsafe input into backend logic that trusts request headers
* Execute HTTP Request Smuggling attacks under some conditions
This issue affects lighttpd1.4.80
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
Affected products
lighttpd · lighttpdRelated CVEs — lighttpd
In the same product, most dangerous first.