How severe is CVE-2026-54465?

No CVSS score has been assigned to CVE-2026-54465 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-54465?

CVE-2026-54465 affects the following packages: websocket-driver (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2026-54465?

Update websocket-driver to 0.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54465 is resolved across your whole dependency graph.

How do I detect CVE-2026-54465 in my RubyGems dependencies?

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

How do I mitigate CVE-2026-54465 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-2026-54465 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-54465 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-2026-54465?

CVE-2026-54465 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th 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-2026-54465?

CVE-2026-54465 is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-54465 published, and has it been updated?

CVE-2026-54465 was published on July 17, 2026 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

CVE-2026-54465 — websocket-driver

Fix: faye/websocket-driver-ruby@17b569f

CVE-2026-54465 is a CWE-770 vulnerability in websocket-driver. A fix is available for websocket-driver — see the affected versions and patch details below.

websocket-driver: Memory exhaustion in HTTP header parser

Also known asGHSA-8j3g-f24p-4mpw

Published

Jul 17, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

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-2026-54465.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

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

Real-World Exposure

1 pkg affected

💎websocket-driver

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

Impact

If this library is used to implement a WebSocket server on top of a TCP server (rather than an HTTP server or framework) using the WebSocket::Driver.server() method, or, if it is used to complement a WebSocket client, then a peer can make a single connection consume an unbounded amount of memory by sending an HTTP request or response with a never-ending list of headers. This can lead to the receiving process running out of memory.

Patches

The issue has been patched in version 0.8.1, by limiting the total size of HTTP request/response lines and headers accepted by the parser to 32 kB. All users should upgrade to this version.

Workarounds

No known workarounds exist.

Acknowledgements

This issue was discovered and reported by Pranjali Thakur, DepthFirst Security Research Team.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`websocket-driver`	all versions	0.8.1`bundle update websocket-driver --conservative`

Affected Products

1 product · 1 configurations

Application

websocket-driverfaye

< 0.8.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for websocket-driver, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update websocket-driver to 0.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54465 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.

Frequently Asked Questions

### Impact If this library is used to implement a WebSocket server on top of a TCP server (rather than an HTTP server or framework) using the `WebSocket::Driver.server()` method, or, if it is used to complement a WebSocket client, then a peer can make a single connection consume an unbounded amount of memory by sending an HTTP request or response with a never-ending list of headers. This can lead to the receiving process running out of memory. ### Patches The issue has been patched in version 0.8.1, by limiting the total size of HTTP request/response lines and headers accepted by the parser

O3 Security · Impact-Aware SCA

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