Red Hat Security Advisory: ruby security update
Affects Red Hat rubySource GCVE Database
Not known to be exploited · CVSS 7.6 High : upgrade the Red Hat redhat/ruby package to 9.8 soon.
Data as of 12 Nov 2026, 23:24 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 9.8
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 9 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade the Red Hat redhat/ruby package to 9.8.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Red Hatredhat/rubypkg:rpm/redhat/rubyOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in net-imap versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4 and corresponding patched Ruby packages from Red Hat. Users should apply these updates promptly. As a temporary workaround, users are strongly encouraged to switch from explicit TLS upgrading mechanisms (STARTTLS on port 143) to implicit TLS connections (IMAPS on port 993), which are not vulnerable to this attack vector. This mitigation bypasses the vulnerable STARTTLS negotiation entirely.
Description
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.
References
- access.redhat.com/errata/RHSA-2026:33512 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2468498 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2468499 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_33512.json (opens in a new tab)
- github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp (opens in a new tab)
- github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618 (opens in a new tab)
- github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e (opens in a new tab)
- github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c (opens in a new tab)
- github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da (opens in a new tab)
- github.com/ruby/net-imap/releases/tag/v0.3.10 (opens in a new tab)
- github.com/ruby/net-imap/releases/tag/v0.4.24 (opens in a new tab)
- github.com/ruby/net-imap/releases/tag/v0.5.14 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-42246 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42246.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:37397 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:35895 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33565 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33540 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33514 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33515 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:35866 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:35867 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:34076 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:35834 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33630 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:36099 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33462 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:37238 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33576 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33577 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33721 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33552 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33551 (opens in a new tab)
- suse.com/support/security/rating/ (opens in a new tab)
- ftp.suse.com/pub/projects/security/csaf/rhsa-2026_33512.json (opens in a new tab)
- lists.suse.com/pipermail/suse-liberty-linux-updates/2026-July/006834.html (opens in a new tab)
- suse.com/security/cve/CVE-2026-42246/ (opens in a new tab)
- suse.com/security/cve/CVE-2026-42258/ (opens in a new tab)