How severe is CVE-2026-54428?

CVE-2026-54428 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-54428 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-54428?

CVE-2026-54428 primarily affects Apache Httpcomponents Core. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-54428?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-54428 published?

CVE-2026-54428 was published on 2026-07-01 and last updated on 2026-07-06.

CVE-2026-54428

CVE-2026-54428 is a high-severity vulnerability in Apache Httpcomponents Core with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Apache Httpcomponents Core
Published: 2026-07-01
Last modified: 2026-07-06

Description

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.

Frequently asked questions

What is CVE-2026-54428?: 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.
How severe is CVE-2026-54428?: CVE-2026-54428 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-54428 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-54428?: CVE-2026-54428 primarily affects Apache Httpcomponents Core. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-54428?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-54428 published?: CVE-2026-54428 was published on 2026-07-01 and last updated on 2026-07-06.

References

Affected products (3)

cpe:2.3:a:apache:httpcomponents_core:*:*:*:*:*:*:*:*
cpe:2.3:a:apache:httpcomponents_core:5.5:alpha1:*:*:*:*:*:*
cpe:2.3:a:apache:httpcomponents_core:5.5:beta1:*:*:*:*:*:*

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