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High

Uncontrolled Recursion DoS in Apache bRPC json2pb

IdentifiersCVE-2025-59789CWE-674· Uncontrolled Recursion

CVE-2025-59789 is an uncontrolled recursion vulnerability in the json2pb component of Apache bRPC affecting versions prior to 1.15.0. The issue arises because json2pb uses RapidJSON to parse JSON input, and RapidJSON's default parsing behavior is recursive. When a bRPC server or application processes attacker-supplied JSON containing excessively deep nested structures, the recursive parser can exhaust the process stack and crash. The vulnerable scenarios described are bRPC servers using protobuf messages to serve HTTP+JSON requests from untrusted networks, and applications that directly call JsonToProtoMessage on untrusted input. The fix introduces a recursion depth limit, defaulting to 100, and applies to ProtoMessageToJson, ProtoMessageToProtoJson, JsonToProtoMessage, and ProtoJsonToProtoMessage.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

A remote attacker can trigger stack exhaustion and crash the affected server or process by sending deeply nested recursive JSON data. Based on the provided information, the impact is denial of service rather than code execution: the target becomes unavailable or the request-handling process terminates when the parser overflows the stack.

Mitigation

If you can’t patch tonight, do this now.

Until the fix is deployed, reduce exposure by preventing untrusted clients from sending arbitrary deep JSON payloads to affected bRPC HTTP+JSON endpoints, especially those converting JSON into protobuf messages. Where possible, place affected services behind input validation, schema enforcement, request filtering, API gateways, or WAF controls that reject excessively nested JSON. Restrict network access to trusted clients only. For deployments that must accept nested data, monitor for crashes and anomalous requests indicative of deep-recursion payloads. After patching, tune json2pb_max_recursion_depth to a safe value appropriate for expected message structures.

Remediation

Patch, then assume compromise.

Upgrade Apache bRPC to version 1.15.0 or later, which includes the fix for CVE-2025-59789. If an upgrade is not immediately possible, apply the patch referenced in Apache bRPC pull request #3099. The fix adds a recursion depth limit with a default value of 100. After remediation, review application behavior for legitimate JSON or protobuf payloads with nesting deeper than the configured limit, and adjust the json2pb_max_recursion_depth gflag if operationally necessary.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Apache Software FoundationBrpcapplication

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ACTIVITY FEED

Recent activity

9 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

9 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity7

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2025-59789
NVD
nvd.nist.gov/vuln/detail/CVE-2025-59789
MITRE CWE · CWE-674
Uncontrolled Recursion
Patch
lists.apache.org/thread/ozmcsztcpxn61jxod8jo8q46jo0oc1zx
Third Party Advisory
openwall.com/lists/oss-security/2025/12/01/1