CVE-2026-42536: apache software foundation apache http server Heap-based Buffer Overflow
CVSS: 7.5v3.1HighModified
AliasesALPINE-CVE-2026-42536UBUNTU-CVE-2026-42536DEBIAN-CVE-2026-42536
Published 08-06-2026Last modified 14-09-2026
Vulnerability summary
CVE-2026-42536 is a high (CVSS 7.5) Heap-based Buffer Overflow vulnerability in apache software foundation apache http server. EPSS estimates a 2.69% chance of exploitation in the next 30 days, higher than 85.6% of scored vulnerabilities.
CVSS score
7.5/10
010
High · v3.1 (CVE.org)EPSS score
2.69%
0%100%
Low · +1.66 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 18 · Related 8Timeline
- 08-06-2026PublishedVulnerability first disclosed.
- 14-09-2026Last modifiedVulnerability information updated.
Description
Heap-based Buffer Overflow vulnerability in Apache HTTP Server with mod_xml2enc, xml2StartParse, and untrusted content This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.
CVSS metrics
5 scores · 5 sources · 1 versionHigh 7.5Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSourcesAll 5 agree
- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
2.69%
Chance of exploitation in the next 30 days
Percentile
86%
Versus all other CVEs
30-day change
+1.66 pp
From 1.02% on 19-09-2026
19-09-202619-10-2026
EPSS score2.69%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
- CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
Affected systems
Alpine1 product
- apache2< 2.4.68-r0
Apache1 product
- http_server≥ 2.4.0, < 2.4.68
Apache software foundation1 product
- apache http server≥ 2.4.0, ≤ 2.4.67
Debian1 product
- apache2< 2.4.68-1~deb12u1 | < 2.4.68-1~deb13u1 | < 2.4.68-1
Ubuntu1 product
- apache2< 2.4.7-1ubuntu4.22+esm14 | < 2.4.18-2ubuntu3.17+esm19 | < 2.4.29-1ubuntu4.27+esm10 | < 2.4.41-4ubuntu3.23+esm5 | < 2.4.52-1ubuntu4.23 | < 2.4.58-1ubuntu8.15 | All versions (No fix recorded) | < 2.4.66-2ubuntu2.4
5 vendors · 5 products
