How severe is CVE-2026-54463?

CVE-2026-54463 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-54463 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-54463?

CVE-2026-54463 affects Faye Websocket-driver. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-54463?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-54463 published?

CVE-2026-54463 was published on 2026-07-17 and last updated on 2026-08-06.

CVE-2026-54463

CVE-2026-54463 is a high-severity vulnerability in Faye Websocket-driver with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.9
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Affected product: Faye Websocket-driver
Published: 2026-07-17
Last modified: 2026-08-06

Description

websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.8.1, draft versions of the WebSocket protocol in websocket-driver include a length header that allows an arbitrarily large integer to be encoded as bytes with the high bit set, and a server or client can send an indefinite sequence of 0x80 or higher bytes that the peer parses into an ever-growing Ruby integer. This can make a WebSocket connection consume an unbounded amount of memory and lead to the host process running out of memory. This issue is fixed in version 0.8.1.

Frequently asked questions

What is CVE-2026-54463?: websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.8.1, draft versions of the WebSocket protocol in websocket-driver include a length header that allows an arbitrarily large integer to be encoded as bytes with the high bit set, and a server or client can send an indefinite sequence of 0x80 or higher bytes that the peer parses into an ever-growing Ruby integer. This can make a WebSocket connection consume an unbounded amount of memory and lead to the host process running out of memory. This issue is fixed in version 0.8.1.
How severe is CVE-2026-54463?: CVE-2026-54463 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-54463 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-54463?: CVE-2026-54463 affects Faye Websocket-driver. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-54463?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-54463 published?: CVE-2026-54463 was published on 2026-07-17 and last updated on 2026-08-06.

References

Affected products (1)

cpe:2.3:a:faye:websocket-driver:*:*:*:*:*:ruby:*:*

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