CVE-2026-87721
Denial of Service via Exponential Backtracking in ANTLR Search Query Parser in Gerrit Code Review
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.
INFO
Published Date :
Sept. 24, 2026, 10:17 p.m.
Last Modified :
Sept. 24, 2026, 10:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-87721
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 14ed7db2-1595-443d-9d34-6215bf890778 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update to Gerrit Code Review 3.12.10 or later.
- Update to Gerrit Code Review 3.13.9 or later.
- Update to Gerrit Code Review 3.14.3 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-87721.
| URL | Resource |
|---|---|
| https://issues.gerritcodereview.com/issues/541287630 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-87721 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-87721
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-87721 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-87721 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Sep. 24, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-407 Added CWE CWE-400 Added CWE CWE-834 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/87xxx/CVE-2026-87721.json">CVE-2026-87721</a> Added Reference https://issues.gerritcodereview.com/issues/541287630