CVE-2023-45802: Apache HTTP Server: HTTP/2 stream memory not reclaimed right away on RST
Vulnerability summary
CVE-2023-45802 is a medium (CVSS 5.9) Improper Resource Shutdown or Release vulnerability in apache software foundation apache http server. EPSS estimates a 3.17% chance of exploitation in the next 30 days, higher than 88% of scored vulnerabilities.
Not severe (CVSS 5.9, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 11 · Related 4Timeline
- 23-10-2023PublishedVulnerability first disclosed.
- 14-10-2024Last modifiedVulnerability information updated.
Description
When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that. This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out. Users are recommended to upgrade to version 2.4.58, which fixes the issue.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · AlpineEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
3.17%
Chance of exploitation in the next 30 days
Percentile
88%
Versus all other CVEs
30-day change
Increase +0.14 pp
From 3.02% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Suse21 products
- apache2-tls13&distro=SUSE Linux Enterprise Server 12 SP5-LTSS< 2.4.51-35.66.1
- apache2-tls13&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5< 2.4.51-35.66.1
- apache2&distro=SUSE Enterprise Storage 7.1< 2.4.51-150200.3.76.1
- apache2&distro=SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS< 2.4.51-150200.3.76.1
- apache2&distro=SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS< 2.4.51-150200.3.76.1
Debian2 products
- apache2< 2.4.59-1~deb12u1 | < 2.4.58-1
- debian_linuxEOL10.0
Alpine1 product
- apache2< 2.4.58-r0
Apache1 product
- http_server≥ 2.4.17, < 2.4.58
Apache software foundation1 product
- apache http server≥ 2.4.17, ≤ 2.4.57
Fedoraproject1 product
- fedoraEOL37 | 38 | 39
Opensuse1 product
- apache2&distro=openSUSE Leap 15.5< 2.4.51-150400.6.40.1 | < 2.4.51-150400.6.43.1
Ubuntu1 product
- apache2< 2.4.29-1ubuntu4.27+esm7 | < 2.4.41-4ubuntu3.15 | < 2.4.52-1ubuntu4.7 | < 2.4.58-1ubuntu1
8 vendors · 29 products
References
23 links- httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisory
lists.debian.org/debian-lts-announce/2024/05/msg00013.htmlX TransferredMailing ListThird Party Advisory
