CVE-2026-39806: mtrudel bandit · Infinite Loop
Affects mtrudel banditSource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 1.11.1 soon.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.11.1, ae3520dfdbfab115c638f8c7f6f6b805db34e1ab
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 13 May 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 bandit to 1.11.1; bandit to ae3520dfdbfab115c638f8c7f6f6b805db34e1ab.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| mtrudelbandit | Affected
| Fixed in
|
| mtrudelbandit | Affected
| Fixed in
|
Hexbanditpkg:hex/banditOther threats | Affected
| Fixed in– |
Hexbanditpkg:hex/banditOther threats | Affected
| Fixed in
|
CPE configurations (1)
cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, consider limiting or filtering requests with trailer fields at upstream proxies if feasible to reduce exposure.
Description
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in mtrudel bandit allows unauthenticated remote denial of service via worker process exhaustion. 'Elixir.Bandit.HTTP1.Socket':do_read_chunked_data!/5 in lib/bandit/http1/socket.ex terminates only when the last-chunk line 0\r\n is followed immediately by the empty trailer line \r\n. RFC 9112 §7.1.2 permits zero or more trailer fields between them. When trailers are present, none of the match clauses fit: the catch-all arm computes a negative to_read, calls read_available!/2, receives <<>> on timeout, and tail-recurses with unchanged state. The worker process is pinned for the lifetime of the TCP connection. A handful of concurrent connections sending RFC-conformant chunked requests with trailer fields is sufficient to exhaust the Bandit worker pool and render the server unresponsive to all further traffic. No authentication, special headers, or large payload is required. Proxies such as NGINX and HAProxy legitimately forward trailer-bearing requests, so servers behind such proxies may be affected without any malicious client involvement. This issue affects bandit: from 1.6.1 before 1.11.1.
References
- github.com/mtrudel/bandit/security/advisories/GHSA-rf5q-vwxw-gmrf (opens in a new tab)
- cna.erlef.org/cves/CVE-2026-39806.html (opens in a new tab)
- osv.dev/vulnerability/EEF-CVE-2026-39806 (opens in a new tab)
- github.com/mtrudel/bandit/commit/ae3520dfdbfab115c638f8c7f6f6b805db34e1ab (opens in a new tab)