CVE-2026-66858: Apache Thrift, Apache Thrift, Apache Thrift, Apache Thrift, Apache Thrift, Apache Thrift: skip() does not apply the recursion limit (Python accelerator, PHP, Perl, Lua, Smalltalk, OCaml)

Severity: high (CVSS 8.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-02 · updated 2026-10-02
Weakness: CWE-674

Description

The protocol skip routine in several Apache Thrift bindings did not apply the binding's recursion limit, so a message that nests unknown fields deeply enough can exhaust the stack. Affected: the Python C++ accelerator (the pure-Python protocols are not affected), the PHP library and its thrift_protocol extension, and the Perl, Lua, Smalltalk and OCaml libraries. This issue affects Apache Thrift: before 0.25.0. Users are recommended to upgrade to version 0.25.0, which fixes the issue.

Affected products

Apache Software Foundation Apache Thrift: before 0.25.0 — fixed in 0.25.0

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Thrift 0.25.0. Check the vendor advisory for mitigations.

References

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