CVE-2026-126190: Soup Sieve · Polynomial-time denial of service in the descendant combinator
Affects flexgetSource GCVE Database
Not known to be exploited · CVSS 7.5 High : upgrade to 3.22.11 soon.
Data as of 13 Nov 2026, 21:16 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 7.5 |
|---|
- Patch
- Available – fixed in 3.22.11
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 Nov 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 13 Nov 2026.
What to do
Upgrade flexget to 3.22.11.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewflexgetpkg:brew/flexgetOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in Soup Sieve version 3.22.11 and later. Users should upgrade to this version or newer to eliminate the vulnerability. The fix introduces caching that reduces the matching time complexity to linear. If upgrading is not possible, users should minimize the use of descendant combinators in selectors applied to untrusted documents, limit the size and nesting depth of such documents, or run selection operations with time limits (e.g., in a separate worker process). The caching mechanism is enabled by default, and no code changes beyond upgrading are needed.
Description
CVE-2026-126190 is a denial of service vulnerability in Soup Sieve's handling of CSS selectors with descendant combinators. The matching algorithm exhibits polynomial time complexity relative to document nesting depth, causing excessive CPU usage on deeply nested documents. This affects applications that run such selectors on untrusted HTML or XML input. The issue is fixed in Soup Sieve version 3.22.11 and later.
References
- github.com/facelessuser/soupsieve/security/advisories/GHSA-mmhr-3c5m-f64f (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-126190 (opens in a new tab)
- github.com/facelessuser/soupsieve/pull/351 (opens in a new tab)
- github.com/facelessuser/soupsieve/commit/ff1a5ce7e5addc31626d7b6053511fecdb4f6320 (opens in a new tab)
- github.com/facelessuser/soupsieve (opens in a new tab)
- github.com/facelessuser/soupsieve/releases/tag/4.0 (opens in a new tab)