Vulnerability · Published Oct 26, 2026 · Assigned by EEF

CVE-2026-108525HTTP/2 inbound flow control is not enforced, letting a client queue unbounded DATA in stream processes in Bandit

High 8.7

In plain English

A high-severity resource allocation without limits in bandit from mtrudel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities).

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.6%top 51.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory via DATA frames sent past the advertised receive window. The attacker requests a response larger than the 65,535-byte initial window and withholds WINDOW_UPDATE, so the stream process blocks while sending and stops reading, then floods small DATA frames on that stream. Every frame is queued in the stream's mailbox until the BEAM node runs out of memory. Bandit.HTTP2.Connection.handle_frame/3 in lib/bandit/http2/connection.ex forwards each DATA frame to the stream process without consulting the receive window, and Bandit.HTTP2.FlowControl.compute_recv_window/2 replenishes the window as data arrives rather than as it is consumed, and never answers a violation with FLOW_CONTROL_ERROR. This issue affects bandit: from 0.3.1 before 1.14.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Ubuntu:22.04:LTS	bandit	no fix listed	UBUNTU-CVE-2026-108525
Ubuntu:24.04:LTS	bandit	no fix listed	UBUNTU-CVE-2026-108525
Ubuntu:26.04:LTS	bandit	no fix listed	UBUNTU-CVE-2026-108525
Ubuntu:26.10	bandit	no fix listed	UBUNTU-CVE-2026-108525

Affected products (as reported)

Vendor	Product	Versions
mtrudel	bandit	0.3.1 – before 1.14.0
mtrudel	bandit	c8dc1e97050cf359f61ed6cdd110f3cdaf1d6f5f – before 220b9dfd27f9a21305be2afc75cbe585ddc24e7a

Weakness: CWE-770 · 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

References

HTTP/2 inbound flow control is not enforced, letting a client queue unbounded DATA in stream processes in Bandit vendor-advisory, related
EEF CNA record for CVE-2026-108525 related
OSV record EEF-CVE-2026-108525 related
Introducing commit c8dc1e9 in mtrudel/bandit related
Fix commit 220b9df in mtrudel/bandit patch