CVE-2026-92790: Higress before 2.2.4 Rate Limit Bypass via Malformed Cookie Header

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-09-24
Weakness: CWE-703

Description

Higress before 2.2.4 panics when processing a Cookie header segment without an equals sign, causing the plugin wrapper to recover and return a continue action that bypasses AI token rate limiting. Unauthenticated attackers can craft a malformed Cookie header to skip rate limit checks and exceed thresholds intended to restrict costly model backend calls.

Affected products

higress-group higress: before 2.2.4 — fixed in 2.2.4

How to fix

Upgrade to a fixed version: higress-group higress 2.2.4. Check the vendor advisory for mitigations.

References

https://github.com/higress-group/higress
https://github.com/higress-group/higress/blob/v2.2.3/plugins/wasm-go/extensions/ai-token-ratelimit/util/utils.go#L52-L63
https://github.com/higress-group/higress/blob/v2.2.4/plugins/wasm-go/extensions/ai-token-ratelimit/util/utils.go#L52-L63
https://github.com/higress-group/higress/issues/4599
https://www.vulncheck.com/advisories/higress-before-2.2.4-rate-limit-bypass-via-malformed-cookie-header
https://github.com/higress-group/higress/issues/4599

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