---
id: CVE-2026-66858
title: >-
  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
summary: >-
  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 pr…
severity: high
cvss: 8.7
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-674
vendor: Apache Software Foundation
product: thrift
affected:
  - thrift < 0.25.0
  - apache/thrift < 0.25.0
  - Thrift < 0.25.0
  - Lua < 0.25.0
  - Smalltalk < 0.25.0
  - OCaml < 0.25.0
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T13:17:53.453'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-66858'
references:
  - url: 'https://lists.apache.org/thread/33otcgbqd27wf6qq810q56znzbomnhg1'
    label: security@apache.org
  - url: 'https://lists.apache.org/thread/6kl6g40tpl8zt3opd8fwn6bsgyddzhd5'
    label: security@apache.org
tags:
  - nvd
  - cve.org
cvssSource: cna
ingestedAt: '2026-10-02T13:19:14.160Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.