High severity · published Oct 26, 2026
CVE-2026-110499
Client-chosen HPACK encoder table size is applied uncapped, growing per-connection state with every response in Bandit
New
8.7
CVSS
0.6%
EPSS
No
On KEV
Description
Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to grow per-connection memory and CPU cost without bound via a large SETTINGS_HEADER_TABLE_SIZE. Bandit resizes its HPACK encoder table to whatever size the client advertises, up to 2^32-1 bytes, and indexes response headers into it. Because responses carry distinct values such as date or content-length, nothing is evicted and the table grows with every response for the life of the connection, while each lookup scans it linearly.
The SETTINGS handling in Bandit.HTTP2.Connection (lib/bandit/http2/connection.ex) passes remote_settings.header_table_size to HPAX.resize/2 with no server-side cap, and encode_headers encodes every response header as :store. Serving N responses on one connection therefore costs O(N²) CPU in the connection process.
This issue affects bandit: from 0.3.6 before 1.14.0.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 49% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BA
bandit · mtrudel
0.3.6 before 1.14.0; 0e68313fab9d204257ebad5c447e4cd9cea8e0ea before 220b9dfd27f9a21305be2afc75cbe585ddc24e7a · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-110499
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-110499
cna.erlef.org
https://cna.erlef.org/cves/CVE-2026-110499.html
github.com
https://github.com/mtrudel/bandit/commit/0e68313fab9d204257ebad5c447e4cd9cea8e0ea
github.com
https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a
github.com
https://github.com/mtrudel/bandit/security/advisories/GHSA-47x4-3fxf-82fr
osv.dev
https://osv.dev/vulnerability/EEF-CVE-2026-110499
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