How severe is CVE-2024-26146?

CVE-2024-26146 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2024-26146?

CVE-2024-26146 affects the following packages: rack (RubyGems), rack (RubyGems), rack (RubyGems), rack (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2024-26146?

Update rack to 3.0.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-26146 is resolved across your whole dependency graph.

How do I detect CVE-2024-26146 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rack, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-26146 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2024-26146 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-26146 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-26146?

CVE-2024-26146 has an EPSS (Exploit Prediction Scoring System) score of 2.0%, placing it in the 81th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-26146?

CVE-2024-26146 is classified as CWE-1333 (CWE-1333). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-26146 published, and has it been updated?

CVE-2024-26146 was published on February 28, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎

💎 RubyGems

Not in CISA KEV

MEDIUM severity

CVE-2024-26146 — rack

MEDIUMFix: rack/rack@30b8e39

CVE-2024-26146 is a medium-severity (CVSS 5.3) CWE-1333 vulnerability in rack. A fix is available for rack — see the affected versions and patch details below.

Possible Denial of Service Vulnerability in Rack Header Parsing

Also known asGHSA-54rr-7fvw-6x8f

Published

Feb 28, 2024

Updated

Oct 28, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-26146.

EPSS Exploitation Probability

via FIRST.org ↗

2.0%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs81th percentile — riskier than 81% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

4 pkgs affected

💎rack💎rack💎rack💎rack

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

Possible Denial of Service Vulnerability in Rack Header Parsing

There is a possible denial of service vulnerability in the header parsing routines in Rack. This vulnerability has been assigned the CVE identifier CVE-2024-26146.

Versions Affected: All. Not affected: None Fixed Versions: 2.0.9.4, 2.1.4.4, 2.2.8.1, 3.0.9.1

Impact

Carefully crafted headers can cause header parsing in Rack to take longer than expected resulting in a possible denial of service issue. Accept and Forwarded headers are impacted.

Ruby 3.2 has mitigations for this problem, so Rack applications using Ruby 3.2 or newer are unaffected.

Releases

The fixed releases are available at the normal locations.

Workarounds

There are no feasible workarounds for this issue.

Patches

To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

2-0-header-redos.patch - Patch for 2.0 series
2-1-header-redos.patch - Patch for 2.1 series
2-2-header-redos.patch - Patch for 2.2 series
3-0-header-redos.patch - Patch for 3.0 series

Credits

Thanks to svalkanov for reporting this and providing patches!

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`rack`	≥ 3.0.0&&< 3.0.9.1	3.0.9.1`bundle update rack --conservative`
💎RubyGems	`rack`	≥ 2.2.0&&< 2.2.8.1	2.2.8.1`bundle update rack --conservative`
💎RubyGems	`rack`	≥ 2.1.0&&< 2.1.4.4	2.1.4.4`bundle update rack --conservative`
💎RubyGems	`rack`	all versions	2.0.9.4`bundle update rack --conservative`

Affected Products

2 products · 4 configurations

debian linuxdebian

1 version

10.0

Application

rackrack

≥ 2.2.0 && < 2.2.8.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rack, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rack to 3.0.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-26146 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Workaround published by Red Hat

No mitigation is currently available for this vulnerability. The recommendation is to perform updates as soon as they are available.

Source: Red Hat security advisory for CVE-2024-26146 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Enterprise Linux 8	`pcs-0:0.10.18-2.el8_10`	RHSA-2024:2953
Red Hat Enterprise Linux 8.2 Telecommunications Update Service	`pcs-0:0.10.4-6.el8_2.5`	RHSA-2024:2007
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	`pcs-0:0.10.8-1.el8_4.5`	RHSA-2024:2584
Red Hat Enterprise Linux 8.6 Extended Update Support	`pcs-0:0.10.12-6.el8_6.5`	RHSA-2024:3431
Red Hat Enterprise Linux 8.8 Extended Update Support	`pcs-0:0.10.15-4.el8_8.2`	RHSA-2024:2581
Red Hat Enterprise Linux 9	`pcs-0:0.11.7-2.el9_4`	RHSA-2024:2113
Red Hat Enterprise Linux 9.0 Extended Update Support	`pcs-0:0.11.1-10.el9_0.5`	RHSA-2024:1841
Red Hat Enterprise Linux 9.2 Extended Update Support	`pcs-0:0.11.4-7.el9_2.1`	RHSA-2024:1846

Frequently Asked Questions

# Possible Denial of Service Vulnerability in Rack Header Parsing There is a possible denial of service vulnerability in the header parsing routines in Rack. This vulnerability has been assigned the CVE identifier CVE-2024-26146. Versions Affected: All. Not affected: None Fixed Versions: 2.0.9.4, 2.1.4.4, 2.2.8.1, 3.0.9.1 Impact ------ Carefully crafted headers can cause header parsing in Rack to take longer than expected resulting in a possible denial of service issue. Accept and Forwarded headers are impacted. Ruby 3.2 has mitigations for this problem, so Rack applications us

O3 Security · Impact-Aware SCA

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