CVE-2026-54399: Uncontrolled Resource Consumption vulnerability in the HTTP/1.1 message parser in Apache HttpComponents Core (

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HIGH 7.5REMOTEWATCHLISTUPGRADE

CVE-2026-54399 is a high-severity flaw (CVSS 7.5) affecting httpcomponents core. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Uncontrolled Resource Consumption vulnerability in the HTTP/1.1 message parser 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 messages with excessive number of headers / excessive header length

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-400
Published	2026-07-01
Last modified	2026-10-25

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-01 17:16 UTCPublished CVE record published
2026-10-25 17:10 UTCUpdated Record last modified

apache httpcomponents core UPGRADE

Affected: >= 5.0 and <= 5.4.2 · 5.5 alpha1 · 5.5 beta1

Fixed in: newer than 5.4.2

Safe to downgrade to: a release before 5.0

1. Check installed version

apt-cache policy httpcomponents-core || rpm -q httpcomponents-core || httpcomponents-core --version

2. UPGRADE to newer than 5.4.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade httpcomponents-core

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade httpcomponents-core

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 5.0 (Debian / Ubuntu)

apt-cache madison httpcomponents-core sudo apt install httpcomponents-core=<VERSION_BEFORE_5.0> sudo apt-mark hold httpcomponents-core

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list httpcomponents-core sudo dnf downgrade httpcomponents-core-<VERSION_BEFORE_5.0> sudo dnf versionlock add httpcomponents-core

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-54399?

httpcomponents core: upgrade to newer than 5.4.2. Exact commands for each OS are on this page.

Is CVE-2026-54399 being exploited?

CVE-2026-54399 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-54399 affect?

CVE-2026-54399 affects httpcomponents core. Severity is high (CVSS 7.5). Uncontrolled Resource Consumption vulnerability in the HTTP/1.1 message parser 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 send

How urgent is CVE-2026-54399?

Priority 50/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-54428 HIGH 7.5 UPGRADE Allocation of resources without limits or throttling in the HTTP/2 HPACK decoder in Apache HttpComponents Core

References

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