VulnerabilityPublished 8 Oct 2026Updated 2 Nov 2026

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

Affects scrapySource GCVE Database

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Not known to be exploited · CVSS 4.3 Medium : upgrade to 2.19.0_3 when convenient.

Data as of 3 Nov 2026, 03:16 UTC

CVSS 3.1 base score

4.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 2.19.0_3

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Oct 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 2 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade scrapy to 2.19.0_3.

Affected software

Product	Affected	Fixed in
Homebrewscrapy`pkg:brew/scrapy`Other threats	Affected >=2.9.0 <2.19.0_3	Fixed in 2.19.0_3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available in Twisted version 2.19.0_3 that properly escapes non-wildcard characters before compiling the regex, preventing ReDoS. Users should upgrade to version 2.19.0_3 or later. No other mitigation is required as the issue is fixed in this release.

Description

CVE-2026-106454 is a Regular Expression Denial of Service (ReDoS) vulnerability in the Twisted framework's IMAP implementation. The function wildcardToRegexp() improperly compiles user-supplied IMAP wildcard patterns into regular expressions without escaping non-wildcard characters, allowing crafted patterns to cause catastrophic backtracking. Because Twisted uses a single-threaded event loop, this blocking regex match can freeze all server I/O, resulting in denial of service. An authenticated IMAP client can exploit this by creating a mailbox with a specially crafted name and issuing a LIST command with a malicious pattern, causing the server to hang for extended periods.

Impact

An authenticated IMAP client can cause a denial of service by sending a crafted LIST command with a malicious wildcard pattern that triggers catastrophic backtracking in the regex engine. This blocks the single-threaded Twisted reactor, freezing all server I/O and making the IMAP service unresponsive for extended periods (e.g., ~55 seconds for a 28-character input). No special privileges beyond authentication are required. The vulnerability does not impact confidentiality or integrity but causes availability disruption.

Summary

The vulnerability exists in twisted/mail/imap4.py in the wildcardToRegexp() function, which converts IMAP LIST/LSUB wildcard patterns to Python regex. It replaces IMAP wildcards '*' and '%' with regex equivalents but passes all other characters directly to re.compile() without escaping. This allows an authenticated IMAP client to supply arbitrary regex syntax, including patterns that cause catastrophic backtracking. Because Twisted's reactor is single-threaded and cooperative, a blocking regex match suspends all I/O on the server. Proof-of-concept shows exponential delay growth with crafted patterns like '(a+)+z'. The impact is a denial of service by stalling the server for tens of seconds per request. The fix involves escaping all non-wildcard characters before compiling the regex, preventing injection of malicious regex constructs. The vulnerability affects Twisted versions >=2.9.0 and <2.19.0_3 and is fixed in 2.19.0_3.

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Description

AI analysisMachine-generated, updated 3 Nov 2026, 03:16 UTC

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