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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2025-12642

28
FAUCET Score

CVE-2025-12642 describes a critical vulnerability in lighttpd version 1.4.80, where incorrect merging of trailer fields into headers after HTTP request parsing enables HTTP Header Smuggling attacks. This flaw, rated 9.1 CVSS (CRITICAL), allows unauthenticated attackers to bypass access controls, inject malicious input into backend logic, and potentially execute HTTP Request Smuggling. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
1.4.80CPE matchmatch criteria
cpe:2.3:a:lighttpd:lighttpd:1.4.80:*:*:*:*:*:*:*
>= 1.4.80, < 1.4.81CPE match
cpe:2.3:a:lighttpd:lighttpd:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

6.9MEDIUM

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
NONE
VS Availability
NONE
SS Confidentiality
NONE
SS Integrity
LOW
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.34%
Probability of exploitation in next 30 days
EPSS Percentile
26.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0034 is in the 5th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1
Patch