CVE-2026-126190: Soup Sieve · Polynomial-time denial of service in the descendant combinator
Affects theharvesterSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 4.0 : patch theharvester 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 4.0
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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewtheharvesterpkg:brew/theharvesterOther 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
Upgrade to Soup Sieve version 4.0 or later, where the issue is fixed by caching ancestor match results to ensure linear-time matching. No code changes are required beyond upgrading. If upgrading is not possible, reduce the use of descendant combinators in selectors on untrusted input, prefer child combinators ('a > b') where possible, limit the size and nesting depth of untrusted documents before selection, and consider running selector operations with time limits or in isolated worker processes that can be terminated if they run too long.
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 with untrusted input. This can tie up application workers for extended periods. The issue is fixed in Soup Sieve version 4.0 by introducing caching to reduce matching complexity to linear time.
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)