High severity · published Oct 22, 2026
CVE-2026-115482
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…
New
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LS
lsquic · litespeedtech
before 4.9.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-115482
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-115482
foxio.io
https://foxio.io/blog/header-accordions-qpack-amplification-attacks-against-http-3-servers
github.com
https://github.com/litespeedtech/lsquic/compare/v4.8.2...v4.9.0
github.com
https://github.com/litespeedtech/lsquic/pull/666
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