7.5

CVE-2026-42245: ruby net-imap Inefficient Algorithmic Complexity

CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-42245DEBIAN-CVE-2026-42245CGA-44v6-7hqq-4mg4
Published 09-05-2026Last modified 12-05-2026
Open JSON

Vulnerability summary

CVE-2026-42245 is a high (CVSS 7.5) Inefficient Algorithmic Complexity vulnerability in ruby net-imap. EPSS estimates a 0.70% chance of exploitation in the next 30 days, higher than 52.3% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.70%
0%100%
Low · +0.29 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 12 · Related 1
RHSA-2026:33515RHSA-2026:33540RHSA-2026:33551RHSA-2026:33552RHSA-2026:33565RHSA-2026:33576

Timeline

  1. 09-05-2026
    PublishedVulnerability first disclosed.
  2. 12-05-2026
    Last modifiedVulnerability information updated.

Description

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client's CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

CVSS metrics

9 scores · 7 sources · 2 versions

EPSS trend

Probability

0.70%

Chance of exploitation in the next 30 days

Percentile

52%

Versus all other CVEs

30-day change

+0.29 pp

From 0.41% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.70%

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

Chainguard60 products
  • gitlab-rails-ce-18.1< 18.1.6-r10
  • gitlab-rails-ce-18.10< 18.10.5-r1
  • gitlab-rails-ce-18.11< 18.11.3-r1
  • gitlab-rails-ce-18.3All versions (No fix recorded)
  • gitlab-rails-ce-18.4All versions (No fix recorded)
Wolfi16 products
  • jruby-10.1< 10.1.1.0-r1
  • jruby-9.4< 9.4.15.0-r2
  • kube-fluentd-operator< 1.18.2-r70
  • logstash-9.3< 9.3.4-r1
  • logstash-9.3-iamguarded-compat< 9.3.4-r1
Debian2 products
  • ruby3.1All versions (No fix recorded)
  • ruby3.3All versions (No fix recorded)
Ubuntu2 products
  • jrubyAll versions (No fix recorded)
  • ruby3.3All versions (No fix recorded)
Ruby1 product
  • net-imap< 0.4.24 | ≥ 0.5.0, < 0.5.14 | ≥ 0.6.0, < 0.6.4
RubyGems1 product
  • net-imap≥ 0.6.0, < 0.6.4 | ≥ 0.5.0, < 0.5.14 | < 0.4.24

6 vendors · 82 products

References

14 links
Show all 14 references