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Fencer Vulns
medium 5.9

CVE-2026-66754 json

Rouille 0.1.6 - 3.6.2 Reachable Assertion DoS via remove_prefix percent-encoding

published 2026-07-28 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-49888

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

Rouille 0.1.6 through 3.6.2 contains a reachable assertion vulnerability in the Request::remove_prefix function that allows remote unauthenticated attackers to crash the server by sending a crafted percent-encoded URL. Attackers can send a request whose decoded path matches a configured prefix while the raw percent-encoded path does not, causing the assert! to fail and triggering either a 500 error or full process termination depending on the panic configuration.

Patch / fix

  • sccache SLES for SAP applications 16.0, SLES 16.0 0.18.0~2-160000.1.1
  • sccache SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Development Tools 15 SP7 0.17.0~1-150600.10.14.1

suse advisories SUSE-SU-2026:23983-1SUSE-SU-2026:3674-1

  • sccache openSUSE Leap 16.0 0.18.0~2-160000.1.1
  • sccache openSUSE Tumbleweed 0.17.0~1-2.1

opensuse advisories openSUSE-SU-2026:21982-1openSUSE-SU-2026:11527-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.56% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/theopaid/Remote-Denial-of-Service-via-Reachable-Assertion-in-URL-Prefix-Handling-rouille- referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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

Affected products

  • tomaka rouille

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.