Denial of Service via Exponential Backtracking in ANTLR Search Query Parser in Gerrit Code Review (CVE-2026-87721) | HOL Guard CVE

High · CVSS 8.7CVE-2026-87721

Denial of Service via Exponential Backtracking in ANTLR Search Query Parser in Gerrit Code Review

Answer in brief

CVE-2026-87721 records a High severity (CVSS 8.7) vulnerability in Denial of Service via Exponential Backtracking in ANTLR Search Query Parser in Gerrit Code Review. The current sources do not mark it as known exploited. The current feed maps Gerrit/Gerrit (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 24, 2026Updated Sep 24, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Gerrit/Gerrit (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Gerrit/Gerritgeneric	>=2.0.19 <3.12.10 \|\| >=3.13.0 <3.13.9 \|\| >=3.14.0 <3.14.3	3.12.10, 3.13.9, 3.14.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for Gerrit/Gerrit.
Review the reported fix. Update Gerrit/Gerrit to 3.12.10 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Source referenceissues.gerritcodereview.com

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.