CVE-2026-42545Public exploitNetwork attack vector

Worker-process crash via unchecked header conversion

Published May 12, 2026 · Updated May 12, 2026

Improper exception handling in Granian 0.2.0 through 2.7.3 allows remote attackers to crash a WSGI worker via malformed response headers. The WSGI response conversion path calls unwrap on HeaderName and HeaderValue construction, turning invalid application output into a release-build process abort. Exploitation requires attacker influence over a header emitted by the WSGI application; one malformed response kills one worker until it restarts.

CVSS severity5.9
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exception handling in Granian 0.2.0 through 2.7.3 allows remote attackers to crash a WSGI worker via malformed response headers. The WSGI response conversion path calls unwrap on HeaderName and HeaderValue construction, turning invalid application output into a release-build process abort. Exploitation requires attacker influence over a header emitted by the WSGI application; one malformed response kills one worker until it restarts.

The record

CVE
CVE-2026-42545
Published
May 12, 2026
Updated
May 12, 2026
Vendor
Emmett Framework
Product
Granian
Classifications
CWE-248, CWE-755, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=>= 0.2.0, < 2.7.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Emmett Framework · Granianversion=>= 0.2.0, < 2.7.4

Published CVSS scores

5.9GitHub, Inc.CVSS:3.1/AV:N/AC:H/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-248Uncaught Exception
CWE-755Improper Handling of Exceptional Conditions
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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