CVE-2026-43871Network attack vector

Service interruption via unterminated compact varints

Published Jul 27, 2026 · Updated Jul 27, 2026

Infinite loop in Apache Thrift before 0.24.0 allows remote attackers to interrupt Python, Go, PHP, and Java RPC services. TCompactProtocol varint readers continue consuming bytes while bit 7 remains set and, without a byte-count ceiling, never reach a terminating byte. A network-reachable endpoint using an affected binding and the compact protocol can have its processing thread held indefinitely by an overlong varint.

CVSS severity8.7
High
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite loop in Apache Thrift before 0.24.0 allows remote attackers to interrupt Python, Go, PHP, and Java RPC services. TCompactProtocol varint readers continue consuming bytes while bit 7 remains set and, without a byte-count ceiling, never reach a terminating byte. A network-reachable endpoint using an affected binding and the compact protocol can have its processing thread held indefinitely by an overlong varint.

The record

CVE
CVE-2026-43871
Published
Jul 27, 2026
Updated
Jul 27, 2026
Vendor
The Apache Software Foundation
Product
Apache Thrift
Classifications
CWE-835, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <0.24.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Thriftversion=0 <0.24.0

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7Apache Software FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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