CVE-2026-6409

Published: April 16th, 2026
A Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted input. Maliciously structured messages—specifically those containing negative varints or deep recursion—can be used to crash the application, impacting service availability.
Unknown
CVSS v2:

Status

DocFilters Release Package State Justification Comment
26.2 protobuf (3.0.0) Not Affected Code Not Present CVE-2026-6409 affects the Protobuf PHP PECL extension (versions < 4.33.6 and < 5.34.0-RC1), specifically php/src/Google/Protobuf/Internal/CodedInputStream.php. Document Filters uses the C++ protobuf library v3.0.0 compiled from source. The PHP directory does not exist in our protobuf-3.0.0 tree, and the vulnerable PHP CodedInputStream class is not compiled, bundled, or used by Document Filters.
26.1 protobuf (3.0.0) Needs Triage
25.4 protobuf (3.0.0) Needs Triage
25.3 protobuf (3.0.0) Needs Triage
25.2 protobuf (3.0.0) Needs Triage
25.1 protobuf (3.0.0) Needs Triage
24.4 protobuf (3.0.0) Needs Triage
24.4.0 protobuf (3.0.0) Needs Triage
24.3 protobuf (3.0.0) Needs Triage
24.2 protobuf (3.0.0) Needs Triage
24.1 protobuf (3.0.0) Needs Triage
23.3 protobuf (3.0.0) Needs Triage
23.2 protobuf (3.0.0) Needs Triage
23.1 protobuf (3.0.0) Needs Triage
22.4 protobuf (3.0.0) Needs Triage
22.3 protobuf (3.0.0) Needs Triage
22.2 protobuf (3.0.0) Needs Triage
22.1 protobuf (3.0.0) Needs Triage
21.11 protobuf (3.0.0) Needs Triage
21.8 protobuf (3.0.0) Needs Triage
21.5.0 protobuf (3.0.0) Needs Triage
21.2.0 protobuf (3.0.0) Needs Triage
11.4.19.3667 protobuf (3.0.0) Needs Triage
11.4.18.3599 protobuf (3.0.0) Needs Triage
11.4.16.3445 protobuf (3.0.0) Needs Triage
11.4.15.3368 protobuf (3.0.0) Needs Triage
11.4.14.3263 protobuf (3.0.0) Needs Triage
11.4.13.3179 protobuf (3.0.0) Needs Triage
11.4.12.3054 protobuf (3.0.0) Needs Triage
11.4.11.3040 protobuf (3.0.0) Needs Triage
11.4.11.2990 protobuf (3.0.0) Needs Triage
11.4.10.2934 protobuf (3.0.0) Needs Triage
11.4.9.2878 protobuf (3.0.0) Needs Triage
11.4.8.2822 protobuf (3.0.0) Needs Triage

Severity score breakdown

References