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Vulnerabilities

Vulnerability · CVE-2025-12642

lighttpd1.4.80 incorrectly merged trailer fields into headers after http request parsing.

Published Nov 3, 2025 · catalog updated Nov 3, 2025 · lighttpd1.4.80 incorrectly merged trailer

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check this week

CVE-2025-12642 is not in CISA KEV. FIRST estimates a 37.00% chance of exploitation in the next 30 days. Check whether you run lighttpd1.4.80 incorrectly merged trailer.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (lighttpd1.4.80 incorrectly merged trailer).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
37.00%
Remediation
Version ranges on file
Affected products
vendor lighttpd lighttpd 1.4.80 <1.4.81

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

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor lighttpd lighttpd 1.4.80 <1.4.811.4.80 <1.4.81

How to fix CVE-2025-12642

  • Upgrade

    CVE-2025-12642 lists a fix boundary at 1.4.81. Compare the installed build with that boundary before you change production.

  • Version check

    Seen in 1.4.80 <1.4.81

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2025-12642 is not in CISA KEV. FIRST estimates a 37.00% chance of exploitation in the next 30 days. Check whether you run lighttpd1.4.80 incorrectly merged trailer.

Which versions are affected?

Compare what you have installed with lighttpd lighttpd 1.4.80 <1.4.81 1.4.80 <1.4.81. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 37.00%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 3, 2025 · EUVD

    Detected

    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 lightt

  2. Nov 3, 2025 · EUVD

    Updated

    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 lightt

Sources

  • EUVDVulnerability recordEUVD-2025-37517

    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 lo

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 3, 2025. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • EUVDOct 25, 2026