Vulnerability in net-imap (CVE-2026-47241)
Summary
Vulnerability in net-imap (CVE-2026-47241). Risk of unauthorized operations or information disclosure. Exploitable via criteria. Mitigation: upgrade to 0.5.15 or later.
Original description
The description as published by the source.
Summary
Several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed.
Details
Net::IMAP::RawData was hardened in v0.6.4, v0.5.14, and v0.4.24 to reject string arguments that would smuggle an invalid literal-continuation marker onto the wire (CVE-2026-42257, GHSA-hm49-wcqc-g2xg). But the trailing-marker check uses an incorrect regex which does not match {0} or {0+}, so an attacker-controlled seach criteria or fetch attr string ending in {0} or {0+} passes validation and is sent verbatim. Since these arguments are sent as the last argument in the command, they will be followed by CRLF. Although the CRLF was intended to end the command, the server will interpret it as part of a literal prefix. This consumes the next command the client puts on the socket as additional arguments to the current command.
This affects the following command's arguments:
criteriafor#searchand#uid_searchsearch_keysfor#sort,#thread,#uid_sort, and#uid_threadattrfor#fetchand#uid_fetch
The command which contained…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-47241 has been found in net-imap.
Attackers can target a specific entry point like criteria over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade net-imap to 0.5.15 or later.
If unsure, ask your IT team or search "net-imap CVE-2026-47241" on the vendor's site.
CVE-2026-47241 (net-imap) — CWE-162
Attack surface: criteria / attr / search_keys / BAD
Patched: 0.5.15 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-162) exists in net-imap. Attackers reach the vulnerable code path via criteria.
Check the vendor advisory for the affected versions of net-imap. Attack surface: criteria / attr / search_keys / BAD.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 0.5.15.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'net-imap' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'net-imap' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
net-imapを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade net-imap to 0.5.15ステージング環境で 0.5.15 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-47241 ruby-net-imap Fixed in: 0.5.15-r0
- Debian DEBIAN-CVE-2026-47241 ruby3.1
- Ubuntu UBUNTU-CVE-2026-47241 jruby
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web cve.org