CVE-2026-115482

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-22 · updated 2026-10-22
Weakness: CWE-770

Description

In lsquic before 4.9.0, the HTTP/3 implementation can use an excessive amount of memory because the number of buffered header sets is not limited, as demonstrated by a QPACK amplification attack. This is related to header_out_dynamic_entry and es_max_header_list_size.

Affected products

litespeedtech LSQUIC: before 4.9.0 — fixed in 4.9.0

How to fix

Upgrade to a fixed version: litespeedtech LSQUIC 4.9.0. Check the vendor advisory for mitigations.

References

https://foxio.io/blog/header-accordions-qpack-amplification-attacks-against-http-3-servers
https://github.com/litespeedtech/lsquic/compare/v4.8.2...v4.9.0
https://github.com/litespeedtech/lsquic/pull/666

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