How severe is CVE-2026-54466?

CVE-2026-54466 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 high, and availability none.

Is CVE-2026-54466 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-54466?

CVE-2026-54466 affects Faye Websocket-driver. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-54466?

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-2026-54466 published?

CVE-2026-54466 was published on 2026-07-17 and last updated on 2026-08-06.

CVE-2026-54466

CVE-2026-54466 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-130.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 9.2
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-130
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 0.7.5, the frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite sequence of bytes with values 0x80 or above, a client can make the server parse these bytes into an ever-growing integer in lib/websocket/driver/draft75.js; because JavaScript numbers are 64-bit floating point values, this number will eventually lose precision and lead to the subsequent payload being parsed incorrectly. This issue is fixed in version 0.7.5.

Frequently asked questions

What is CVE-2026-54466?: websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.7.5, the frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite sequence of bytes with values 0x80 or above, a client can make the server parse these bytes into an ever-growing integer in lib/websocket/driver/draft75.js; because JavaScript numbers are 64-bit floating point values, this number will eventually lose precision and lead to the subsequent payload being parsed incorrectly. This issue is fixed in version 0.7.5.
How severe is CVE-2026-54466?: CVE-2026-54466 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 high, and availability none.
Is CVE-2026-54466 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-54466?: CVE-2026-54466 affects Faye Websocket-driver. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-54466?: 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-2026-54466 published?: CVE-2026-54466 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:*:*

More vulnerabilities in Faye Websocket-driver

CVE-2026-54465 — High (CVSS 7.5): websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.8.1, when websocket-driver is used to…
CVE-2026-54463 — High (CVSS 7.5): websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.8.1, draft versions of the WebSocket…

All CVEs affecting Faye Websocket-driver →

Other CWE-130 vulnerabilities

CVE-2022-2714 — Critical (CVSS 9.8): Improper Handling of Length Parameter Inconsistency in GitHub repository francoisjacquet/rosariosis prior to 10.0.
CVE-2026-9054 — Critical (CVSS 9.2): An attacker sending tcp, il, rudp, rudp, or gre packets with a length less than the header size would trigger a kernel…
CVE-2022-1543 — High (CVSS 8.8): Improper handling of Length parameter in GitHub repository erudika/scoold prior to 1.49.4. When the text size is large…
CVE-2026-3868 — High (CVSS 8.7): An improper handling of the length parameter inconsistency vulnerability has been identified in Moxa’s Secure…
CVE-2026-5367 — High (CVSS 8.6): A flaw was found in OVN (Open Virtual Network). A remote attacker, by sending crafted DHCPv6 (Dynamic Host…
CVE-2022-20870 — High (CVSS 8.6): A vulnerability in the egress MPLS packet processing function of Cisco IOS XE Software for Cisco Catalyst 3650,…

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