6.5

CVE-2026-26962: rack CRLF Injection

CVSS: 6.5v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-26962DEBIAN-CVE-2026-26962CGA-36xg-gfm6-9xfh
Published 02-04-2026Last modified 03-04-2026
Open JSON

Vulnerability summary

CVE-2026-26962 is a medium (CVSS 6.5) CRLF Injection vulnerability in rack. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.7% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.24%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3 · Related 5
OPENSUSE-SU-2026:21640-1SUSE-SU-2026:23321-1SUSE-SU-2026:2487-1CGA-99F4-28J2-7VXMUSN-8182-1

Timeline

  1. 02-04-2026
    PublishedVulnerability first disclosed.
  2. 03-04-2026
    Last modifiedVulnerability information updated.

Description

Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6.

CVSS metrics

6 scores · 6 sources · 1 version

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

15%

Versus all other CVEs

30-day change

+0.02 pp

From 0.23% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.24%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard6 products
  • pact-broker-docker< 2.137.0.2.118.0-r4
  • pact-broker-docker-fips< 2.137.0.2.118.0-r2
  • ruby3.2-rails-7.2< 7.2.3.1-r1 | < 7.2.3.1-r2
  • ruby3.2-rails-8.0< 8.0.5-r0
  • ruby3.4-rails-7.2< 7.2.3.1-r1
Debian1 product
  • ruby-rack< 3.1.20-0+deb13u2 | < 3.2.6-2
Rack1 product
  • rack≥ 3.2.0, < 3.2.6
RubyGems1 product
  • rack≥ 3.2.0, < 3.2.6
Ubuntu1 product
  • ruby-rackAll versions (No fix recorded) | < 2.2.7-1ubuntu0.7 | < 3.1.16-0.1ubuntu0.3

5 vendors · 10 products

References

9 links