What is CVE-2026-87721?
Uncontrolled Resource Consumption (CWE-400 / CWE-407) in the ANTLR 3 search query parser (QueryParser / Query.g) in Gerrit Code Review versions 2.0.19 through 3.12.9, 3.13.0 through 3.13.8, and 3.14.0 through 3.14.2 allows an unauthenticated remote attacker (or an authenticated user if anonymous read access is disabled) to cause a persistent denial of service (CPU exhaustion and HTTP worker thread pool starvation requiring a server restart) via crafted search queries containing deeply nested parentheses sent to query evaluation endpoints (/changes/?q=, /accounts/?q=, /groups/?query=, /projects/?query=, /Documentation/?q=, /changes/{id}/query?expression=, or SSH gerrit query). Because syntactic predicates in conditionOr and conditionAnd recurse via conditionBase without memoization prior to capability or visibility checks and worker threads do not abort when the client disconnects, a small number of requests (such as 25 requests matching default httpd.maxThreads) can permanently pin all HTTP worker threads. This issue is fixed in Gerrit Code Review versions 3.12.10, 3.13.9, and 3.14.3.
The record classifies CVE-2026-87721 under weakness classes CWE-400, CWE-407, CWE-834. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 11 days ago.
Severity and exploitation probability
- CVSS v4.0 base score
- 8.7 — High (derived from score)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - EPSS (FIRST)
- 0.3% probability of exploitation in the next 30 days, higher than 22.7% 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
- 2026-09-24, last modified 2026-09-25
Is CVE-2026-87721 being exploited?
It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.
Affected products and versions
- Gerrit: Gerrit
How to fix CVE-2026-87721
No vendor patch reference has been recorded for CVE-2026-87721 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-2026-87721
No threat campaign in the Threadlinqs corpus currently references CVE-2026-87721, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, FIRST EPSS, NVD. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.