PT-2026-29957 · Julia · Nghttp2 Jll

Published 2026-03-23 · Updated 2026-03-23

OSV

In nghttp2 before version 1.41.0, the overly large HTTP/2 SETTINGS frame payload causes denial of service. The proof of concept attack involves a malicious client constructing a SETTINGS frame with a length of 14,400 bytes (2400 individual settings entries) over and over again. The attack causes the CPU to spike at 100%. nghttp2 v1.41.0 fixes this vulnerability. There is a workaround to this vulnerability. Implement nghttp2 on frame recv callback callback, and if received frame is SETTINGS frame and the number of settings entries are large (e.g., > 32), then drop the connection.

Related Identifiers

JLSEC-2026-1

Affected Products

Nghttp2 Jll

References · 15

• https://debian.org/security/2020/dsa-4696 · Vendor Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AAC2AA36OTRHKSVM5OV7TTVB3CZIGEFL · Vendor Advisory
• https://osv.dev/vulnerability/JLSEC-2026-1 · Vendor Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4OOYAMJVLLCLXDTHW3V5UXNULZBBK4O6 · Vendor Advisory
• https://github.com/nghttp2/nghttp2/security/advisories/GHSA-q5wr-xfw9-q7xr · Note
• https://github.com/nghttp2/nghttp2/commit/f8da73bd042f810f34d19f9eae02b46d870af394 · Note
• https://github.com/nghttp2/nghttp2/commit/336a98feb0d56b9ac54e12736b18785c27f75090 · Note
• https://oracle.com/security-alerts/cpuapr2022.html · Note
• https://oracle.com//security-alerts/cpujul2021.html · Note
• https://oracle.com/security-alerts/cpujan2021.html · Note
• https://oracle.com/security-alerts/cpuoct2020.html · Note
• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00024.html · Note
• https://oracle.com/security-alerts/cpujul2020.html · Note
• https://lists.debian.org/debian-lts-announce/2021/10/msg00011.html · Note
• https://lists.debian.org/debian-lts-announce/2023/10/msg00023.html · Note