PatchTheCVECVE-2026-65623: Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of ser
CVE-2026-65623 is a high-severity flaw (CVSS 8.7) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly. The size guard 'Elixir.Bandit.WebSocket.Connection':oversize_message?/2 called from handle_frame/3 in lib/bandit/websocket/connection.ex appends each non-final continuation frame to a left-nested iolist and then re-measures the entire accumulated buffer with IO.iodata_length/1
Why this priority
- High severity
- CISA SSVC: public proof of concept
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 8.7 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.6% (top 50%) |
| CISA exploited list | No |
| Weakness | CWE-407 |
| Published | 2026-07-24 |
| Last modified | 2026-10-24 |
Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Write-up: cna.erlef.org/cves/CVE-2026-65623.html
- Write-up: github.com/mtrudel/bandit/security/advisories/GHSA-vg8x-66vg-5pxh
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-65623?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-65623 being exploited?
CVE-2026-65623 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-65623 affect?
CVE-2026-65623 affects affected software. Severity is high (CVSS 8.7). Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly. The size guard 'Elixir.Bandit.WebSocket.Connection':oversize_messag
How urgent is CVE-2026-65623?
Priority 51/100. High severity; CISA SSVC: public proof of concept; Remotely exploitable, no login, no user action