Is CVE-2023-43622 in the CISA KEV catalog?

No. CVE-2023-43622 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2023-43622?

CVE-2023-43622 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2023-43622?

CVE-2023-43622 has an EPSS score of 70.59% (99th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2023-43622?

Upgrade apache2 on debian 11 to 2.4.59-1~deb11u1 or later. Fixes are available for 9 affected products.

CVE & CISA-KEV Catalog

CVE-2023-43622

HIGHEPSS 99th pctl

7.5

CVSS v3

NVD

Description

An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout. This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57. Users are recommended to upgrade to version 2.4.58, which fixes the issue.

CWE-400Resource Exhaustion

How to fix

Remediation Available

apache2Debian

Fixed in:2.4.59-1~deb11u1CVE-2023-43622

Fixed in:2.4.59-1~deb12u1CVE-2023-43622

Fixed in:2.4.58-1CVE-2023-43622

mod_http2Rocky

Fixed in:0:2.0.26-1.el9RHSA-2024:2368

mod_http2Red Hat / RHEL

Fixed in:0:2.0.26-1.el9RHSA-2024:2368

mod_http2-debuginfoRocky

Fixed in:0:2.0.26-1.el9RHSA-2024:2368

mod_http2-debuginfoRed Hat / RHEL

Fixed in:0:2.0.26-1.el9RHSA-2024:2368

mod_http2-debugsourceRocky

Fixed in:0:2.0.26-1.el9RHSA-2024:2368

mod_http2-debugsourceRed Hat / RHEL

Fixed in:0:2.0.26-1.el9RHSA-2024:2368

apache2Ubuntu

Fixed in:2.4.41-4ubuntu3.15USN-6506-1

Fixed in:2.4.52-1ubuntu4.7USN-6506-1

Fixed in:2.4.55-1ubuntu2.1USN-6506-1

Fixed in:2.4.57-2ubuntu2.1USN-6506-1

httpdWindows application

Affected:2.4.55 2.4.58Fixed in:2.4.58Apache Lounge

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

70.59%probability of exploitation in 30 days

99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

References

Vendor Advisory1

httpd.apache.org

Third-Party Advisory1

security.netapp.com

Related Vulnerabilities

Other CWE-400 (Resource Exhaustion) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-44487	High	7.5	100%	KEV	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2011-3192	High	7.8	99%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2024-25617	Medium	5.3	89%	-	Fix
CVE-2018-1000115	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-02-13.