snakeviz · tornado: multipart split() creates huge temp list before max_parts check -> memory amplification DoS (httputil.py:34)
Affects snakevizSource GCVE Database
Not known to be exploited · CVSS 8.7 High : upgrade to 2.2.2_5 soon.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.2.2_5
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 15 Sep 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 29 Oct 2026.
What to do
Upgrade snakeviz to 2.2.2_5.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewsnakevizpkg:brew/snakevizOther 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 patch is available and fixed the issue in snakeviz version 2.2.2_5. Users should upgrade to version 2.2.2_5 or later to remediate this vulnerability.
Description
CVE-2026-91990 is a medium severity pre-authentication denial-of-service vulnerability in the multipart form data parsing of the snakeviz product. The function parse_multipart_form_data calls split() on the entire input data before checking the number of parts against a configured maximum, causing excessive memory allocation. This can be exploited by sending a crafted HTTP request with many multipart parts, leading to transient memory amplification and potential service disruption. The issue is fixed in version 2.2.2_5 by changing the approach to count separators without creating a large list.
References
- github.com/tornadoweb/tornado/security/advisories/GHSA-8423-8fgw-73vq (opens in a new tab)
- github.com/tornadoweb/tornado/pull/3704 (opens in a new tab)
- github.com/tornadoweb/tornado/commit/de85b3f87446e323e881bbaa3d5a74f4b76e5f05 (opens in a new tab)
- gist.github.com/afldl/649861f25d39b53b7edbe0298e171617 (opens in a new tab)
- github.com/tornadoweb/tornado (opens in a new tab)
- github.com/tornadoweb/tornado/releases/tag/v6.5.8 (opens in a new tab)