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CVE-2026-6409highCWE-20

Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted input

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.1epss 0.4%
exploitation probability
0.4%top 71% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N