CVE-2026-54428CWE-400CWE-770

Apache HttpComponents Core: HPackDecoder Unlimited Header List Size Before SETTINGS ACK

High · published July 1, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
58.4
In the wild
Unconfirmed
What it is

Allocation of resources without limits or throttling in the HTTP/2 HPACK decoder in Apache HttpComponents Core (5.4.2 and earlier, 5.5-beta1 and earlier) allows an remote attacker to cause a denial of service through memory exhaustion by sending oversized compressed header blocks before the HTTP/2 SETTINGS acknowledgement causes the configured header list size limit to be applied.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00871 · 58.4th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-07-01T17:03Z
EPSS history
Timeline
  • 01 JUL 17:03Z
    Apache HttpComponents Core: HPackDecoder Unlimited Header List Size Before SETTINGS ACK
    cvelistv5