What is CVE-2026-63686?
A NULL pointer dereference in mod_xml2enc in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows an untrusted backend server to cause a denial of service via a proxied response with a charset whose conversion partially succeeds then fails. Users are recommended to upgrade to version 2.4.69, which fixes this issue.
The record classifies CVE-2026-63686 under weakness class CWE-476. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 22 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.5 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS (FIRST)
- 0.4% probability of exploitation in the next 30 days, higher than 39.3% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-10-01
Is CVE-2026-63686 being exploited?
It currently carries a trending score of 43 in the Threadlinqs vulnerability feed.
Affected products and versions
- Apache Software Foundation: Apache HTTP Server
How to fix CVE-2026-63686
No vendor patch reference has been recorded for CVE-2026-63686 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-63686
1 tracked threat in the Threadlinqs corpus references CVE-2026-63686, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on .