Skip to content
Fencer Vulns
medium 6.5

CVE-2026-93711 json

Dancer2 versions before 2.2.0 for Perl do not strip CR and LF from response header names in headers_to_array

published 2026-09-22 48 d ago modified 2026-09-22 47 d ago also EUVD-2026-84257

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

Dancer2 versions before 2.2.0 for Perl do not strip CR and LF from response header names in headers_to_array.

The routine removes CR and LF from each header value but not from the name. A name carrying them therefore reaches the PSGI server intact. A server that does not validate keys writes it to the wire, so the bytes after the CRLF arrive as their own header line.

The application has to derive the header name from request data, not just the value.

An attacker who controls that data adds their own headers and splits the response.

Patch / fix

  • libdancer2-perl Debian 14 2.2.2-1

debian advisories DEBIAN-CVE-2026-93711

  • perl-Dancer2 openSUSE Tumbleweed 2.2.2-1.1

opensuse advisories openSUSE-SU-2026:12202-1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
47 d ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Classification

Weakness
  • CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers

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.