Allocation of Resources Without Limits or Throttling Affecting google/protobuf package, versions <3.25.9>=4.0.0RC1, <4.33.6
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-PHP-GOOGLEPROTOBUF-14943962
- published15 Jan 2026
- disclosed14 Jan 2026
- credit34selen
Introduced: 14 Jan 2026
CVE-2026-6409 (opens in a new tab)How to fix?
Upgrade google/protobuf to version 3.25.9, 4.33.6 or higher.
Overview
google/protobuf is a proto library for PHP
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling due to missing validation in the readRaw() function in the CodedInputStream class. An attacker can exhaust all PHP workers and cause denial of service by sending a crafted Protobuf message with a length-delimited field containing a varint that decodes to a negative length, corrupting the internal cursor and trapping mergeFromString() in an infinite loop.