# CVE-2026-106454: Twisted: IMAP wildcardToRegexp() ReDoS

CVE-2026-106454 is fixed in 2 products on 1 platform, first by python3-twisted 22.1.0-2ubuntu2.8, released October 6, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-106454
- Priority: Routine
- CVSS: 4.3 (Moderate)
- EPSS: 0.0042
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 6, 2026
- Weakness: Inefficient Regular Expression Complexity
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-106454

## Description

Twisted is an event-based framework for internet applications, supporting Python 3.6+. In 25.5.0 and earlier, wildcardToRegexp() in twisted/mail/imap4.py translates the IMAP asterisk and percent wildcards but passes all other characters from an authenticated client's LIST or LSUB pattern directly to re.compile(), allowing nested or otherwise expensive regular expression constructs to cause catastrophic backtracking when matched against mailbox names. Because Twisted uses a cooperative single-threaded reactor, the blocking match suspends all server input and output for the duration of the match. No fixed release is available as of this review.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python3-twisted Ubuntu 22.04.1 LTS (jammy) | 22.1.0-2ubuntu2.8 | [python3-twisted 22.1.0-2ubuntu2.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-twisted-22.1.0-2ubuntu2.8.md) | Oct 6, 2026 |
| Linux | python3-twisted Ubuntu 24.04.5 LTS (noble) | 24.3.0-1ubuntu0.3 | [python3-twisted 24.3.0-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-twisted-24.3.0-1ubuntu0.3.md) | Oct 6, 2026 |
| Linux | python3-twisted Ubuntu 26.04.1 LTS (resolute) | 25.5.0-5ubuntu0.2 | [python3-twisted 25.5.0-5ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-twisted-25.5.0-5ubuntu0.2.md) | Oct 6, 2026 |
| Linux | twisted Debian 14 | 26.4.0-5 | [DEBIAN-CVE-2026-106454](https://patchblox.com/security/data/fix/linux/debian-cve-2026-106454.md) | Oct 20, 2026 |

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Data as of 2026-11-09T19:38:12Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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