Apache bRPC: Uncontrolled Recursion
CVE-2025-59789 is a high-severity uncontrolled recursion vulnerability in Apache bRPC from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 1.15.0 as the first without the flaw, so updating Apache bRPC to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.67% chance of exploitation within 30 days, higher than 77% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache bRPC to 1.15.0 or a later version.
- Update Brpc to 1.15.0 or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache bRPC | before 1.15.0 | 1.15.0 |
| Apache | Brpc | before 1.15.0 | 1.15.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CISA (ADP).
Official description
Uncontrolled recursion in the json2pb component in Apache bRPC (version < 1.15.0) on all platforms allows remote attackers to make the server crash via sending deep recursive json data. Root Cause: The bRPC json2pb component uses rapidjson to parse json data from the network. The rapidjson parser uses a recursive parsing method by default. If the input json has a large depth of recursive structure, the parser function may run into stack overflow. Affected Scenarios: Use bRPC server with protobuf message to serve http+json requests from untrusted network. Or directly use JsonToProtoMessage to convert json from untrusted input. How to Fix: (Choose one of the following options) 1. Upgrade bRPC to version 1.15.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3099 Note: No matter which option you choose, you should know that the fix introduces a recursion depth limit with default value 100. It affects these functions: ProtoMessageToJson, ProtoMessageToProtoJson, JsonToProtoMessage, and ProtoJsonToProtoMessage. If your requests contain json or protobuf messages that have a depth exceeding the limit, the request will be failed after applying the fix. You can modify the gflag json2pb_max_recursion_depth to change the limit.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Uncontrolled Recursion
The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
How developers prevent this class of flaw
- Ensure that an end condition will be reached under all logic conditions. The end condition may include checking against the depth of recursion and exiting with an error if the recursion goes too deep. The complexity of the end condition contributes to the effectiveness of this action.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- openwall.com/lists/oss-security/2025/12/01/1Mailing List, Third Party Advisory
Other vulnerabilities in Apache bRPC
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Uncontrolled Recursion vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 8.6 High severity
- 7.5 High severity
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