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VulnerabilityPublished Updated

CVE-2025-53605: stepancheg protobuf · Uncontrolled Recursion

Affects stepancheg protobufSource CVE Database V5

0

Not known to be exploited · CVSS 5.9 Medium : upgrade to 3.7.2 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.7.2
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade stepancheg protobuf to 3.7.2.

Affected software

ProductAffectedFixed in
crates.ioprotobufpkg:cargo/protobufOther threatsAffected
  • <3.7.2
Fixed in
  • 3.7.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should prioritize upgrading the protobuf crate to version 3.7.2 or later in all Rust projects to eliminate the uncontrolled recursion vulnerability. For applications where immediate upgrade is not feasible, implement input validation and filtering to reject or sanitize protobuf messages containing unknown groups or fields before parsing. Employ runtime monitoring and resource limits to detect and mitigate excessive recursion or stack usage, such as configuring process-level stack size limits or using sandboxing techniques. Conduct thorough code audits to identify any custom protobuf parsing logic that might be vulnerable. Additionally, implement robust logging and alerting to detect anomalous protobuf message patterns indicative of exploitation attempts. Coordinate with software supply chain teams to ensure all dependencies are updated promptly and maintain an inventory of Rust-based components using protobuf. Finally, consider deploying Web Application Firewalls (WAFs) or network-level protections to block suspicious protobuf traffic patterns if protobuf messages are transmitted over network protocols.

Description

The protobuf crate before 3.7.2 for Rust allows uncontrolled recursion in the protobuf::coded_input_stream::CodedInputStream::skip_group parsing of unknown fields in untrusted input.

References

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