CVE-2026-74836Public exploitNetwork attack vector

Unauthenticated process pinning via HTTP/2 flow control

Published Aug 20, 2026 · Updated Aug 20, 2026

Denial of service in Bandit before 1.12.5 allows remote attackers to hang HTTP/2 stream processes via connection-level flow control. In Bandit.HTTP2.Connection, finish_data/5 queues unsent bytes and an unblock closure in pending_sends, while Bandit.HTTP2.Stream.send_data/3 waits in a synchronous call with no timeout or queue purge when the connection send window is exhausted. Any endpoint that returns more than the remaining 65,535-byte connection window is reachable; periodic PING frames keep the socket alive, RST_STREAM does not free the blocked stream, and each stalled request can pin Plug state and pooled upstream resources until the attacker stops the connection.

CVSS severity8.7
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Bandit before 1.12.5 allows remote attackers to hang HTTP/2 stream processes via connection-level flow control. In Bandit.HTTP2.Connection, finish_data/5 queues unsent bytes and an unblock closure in pending_sends, while Bandit.HTTP2.Stream.send_data/3 waits in a synchronous call with no timeout or queue purge when the connection send window is exhausted. Any endpoint that returns more than the remaining 65,535-byte connection window is reachable; periodic PING frames keep the socket alive, RST_STREAM does not free the blocked stream, and each stalled request can pin Plug state and pooled upstream resources until the attacker stops the connection.

The record

CVE
CVE-2026-74836
Published
Aug 20, 2026
Updated
Aug 20, 2026
Vendor
Mat Trudel
Product
Bandit
Classifications
CWE-770, CAPEC-130, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.3.4 <1.12.5
  2. Affected versionversion=6feadb31189d18b7dcda6c663112cd3bbaf63a46 <f6914aad14bb1365dd6f306aa592cfb0819bed3e

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mat Trudel · Banditversion=0.3.4 <1.12.5; version=6feadb31189d18b7dcda6c663112cd3bbaf63a46 <f6914aad14bb1365dd6f306aa592cfb0819bed3e

Published CVSS scores

8.7EEFCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CAPEC-130Excessive Allocation
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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