CVE-2026-77643 Cross-site scripting in xapian-core
An XSS vulnerability in Xapian's snippet generation allows attackers to inject malicious scripts via incomplete HTML escaping.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-77643?
CVE-2026-77643 is a medium-severity cross-site scripting vulnerability in xapian-core, published on 20 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
A cross-site scripting vulnerability in queryparser/termgenerator_internal.cc in Xapian xapian-core before 2.1.0 and before 1.4.32 exists due to incomplete HTML escaping by Xapian::MSet::snippet(). NOTE: this issue exists because of a missed corner case of CVE-2018-0499.
Weakness: CWE-79
Which versions are affected by CVE-2026-77643?
How do I fix CVE-2026-77643?
Upgrade to a fixed version.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-77643 being exploited?
There is no known exploitation of CVE-2026-77643 in the wild and no public exploit code.
Sources
Also known as AZL-96924, DEBIAN-CVE-2026-77643, GHSA-955x-jgcw-hcxh, JLSEC-2026-1387, OESA-2026-4058, UBUNTU-CVE-2026-77643.