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CVE-2026-106454 · GHSA-8pqf-f4m5-798g

Twisted: IMAP wildcardToRegexp() ReDoS

Risk score
41/100
CVSS
4.3 v3.1
Exploit chance (30 days)
0.3%
Published
6 Oct 2026

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What to know

What it is
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(), allo…
Affected
Twisted (pip) <= 26.4.0
Fix
No patched version listed yet: check the advisory for mitigations.
Exploitation
Public proof of concept

Story map

Story map: TwistedTHE FLAWSTHE FIXCVE-2026-106454IMAP wildcardToRegexp()ReDoSCVSS 4.3 · EPSS 0%CVE-2026-115775Unauthenticated Remote Denialof Service in the Twistedwords domish XML Element…CVSS 8.7 · EPSS 1%CVE-2026-115776Unauthenticated Remote Denialof Service in the Twisted IRCServer via an Unbounded Line…CVSS 7.5 · EPSS 1%CVE-2026-115778Unauthenticated Remote Denialof Service in the Twisted conchTelnet Transport via an…CVSS 7.5 · EPSS 1%Upgrade Twisted26.10.0or later on your release lineWho is exposed{'products': ['Twisted'],'packages': ['Twisted'],'versions': ['<= 26.4.0']}AMBER · PATCH THIS WEEKTwistedTwisted has a vulnerability in itsXML parser that allows anunauthenticated remote peer tocause a denial of service bycontinuously adding childelements to an in-memory tree,exhausting server memory and…Where it standsPublic proof of conceptCONNECTS TOSame weaknessCWE-1333 (CWE-1333)43 other warnings in 30 days →
Story map: the flaws, the fix, how it unfolded and what it connects to. Boxes link to the record or article.

At a glance

Twisted: Amber, patch this week. Twisted has a vulnerability in its XML parser that allows an unauthenticated remote peer to cause a denial of service by continuously adding child elements to an in-memory tree, exhausting server memory and terminating the process.

The flaws

  • CVE-2026-106454: IMAP wildcardToRegexp() ReDoS (CVSS 4.3 · EPSS 0%)
  • CVE-2026-115775: Unauthenticated Remote Denial of Service in the Twisted words domish XML Element Stream via an Unbounded Element Tree (CVSS 8.7 · EPSS 1%)
  • CVE-2026-115776: Unauthenticated Remote Denial of Service in the Twisted IRC Server via an Unbounded Line Buffer (CVSS 7.5 · EPSS 1%)
  • CVE-2026-115778: Unauthenticated Remote Denial of Service in the Twisted conch Telnet Transport via an Unbounded Subnegotiation Buffer (CVSS 7.5 · EPSS 1%)

The fix

Upgrade Twisted: 26.10.0 or later on your release line

Who is exposed: {'products': ['Twisted'], 'packages': ['Twisted'], 'versions': ['<= 26.4.0']}

Where it stands

  • Public proof of concept

Connects to

Why it is Yellow

  • CVSS 4.3 medium
  • Public exploit or proof of concept referenced
  • On your watchlist: PyPI

Affected packages

PackageEcosystemVulnerableFixed in
Twistedpip<= 26.4.0No fix yet

References

Original 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.

Last activity 6 Oct 2026. Patch Forecast updates every hour.