CVE-2022-24668: A program using swift-nio-http2 is vulnerable to a denial of service attack caused by a network peer sending ALTSVC or ORIGIN frames.

A program using swift-nio-http2 is vulnerable to a denial of service attack caused by a network peer sending ALTSVC or ORIGIN frames.

A program using swift-nio-http2 is vulnerable to a denial of service attack caused by a network peer sending ALTSVC or ORIGIN frames. This attack affects all swift-nio-http2 versions from 1.0.0 to 1.19.1. This vulnerability is caused by a logical error after frame parsing but before frame handling. ORIGIN and ALTSVC frames are not currently supported by swift-nio-http2, and should be ignored. However, one code path that encounters them has a deliberate trap instead. This was left behind from the original development process and was never removed. Sending an ALTSVC or ORIGIN frame does not require any special permission, so any HTTP/2 connection peer may send such a frame. For clients, this means any server to which they connect may launch this attack. For servers, anyone they allow to connect to them may launch such an attack. The attack is low-effort: it takes very little resources to send one of these frames. The impact on availability is high: receiving the frame immediately crashes the server, dropping all in-flight connections and causing the service to need to restart. It is straightforward for an attacker to repeatedly send these frames, so attackers require very few resourc

Description from the National Vulnerability Database, published by cve@forums.swift.org

What it means for a small business

If your business uses SwiftNIO HTTP2, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 1.1%, higher than 66% of CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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