Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 5.8 | Medium | 4.0 | CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0043, the 37th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 15:16 UTC First seen by agentprime
- 31 Oct 2026, 15:16 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-hm49-wcqc-g2xg
- OSV: GHSA-hm49-wcqc-g2xg
- github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg
- nvd.nist.gov/vuln/detail/CVE-2026-42257
- github.com/ruby/net-imap/commit/0ec4fd351263e8b9a4f683713427827b7b1ad974
- github.com/ruby/net-imap/commit/47c72186d272441878ca73c9499f66013829ca2f
- github.com/ruby/net-imap/commit/6bf02aef7e0b5931010c36e377f79a71636b306b
- github.com/ruby/net-imap/commit/a4f7649c3da77dec7631f03a037a478eb4330048
- github.com/ruby/net-imap/commit/aec06996eb87a7e1bbcef1f9f8926e8add2b8c71
- github.com/ruby/net-imap
- github.com/ruby/net-imap/releases/tag/v0.4.24
- github.com/ruby/net-imap/releases/tag/v0.5.14
- github.com/ruby/net-imap/releases/tag/v0.6.4
- github.com/rubysec/ruby-advisory-db/blob/master/gems/net-imap/CVE-2026-42257.yml