CVE-2026-91135: Apache Thrift: C++ `THeaderTransport::transform()` heap buffer overflow (write direction)

Severity: critical (CVSS 9.2 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-122

Description

Heap-based buffer overflow vulnerability in Apache Thrift C++ THeaderTransport. When an application enables the ZLIB transform for the frames it sends, THeaderTransport::transform() copies the compressed frame into the write buffer without making sure it fits. Data that does not compress, such as content a remote peer supplied, grows under compression, so the copy writes past the end of the heap buffer by an amount that grows with the size of the frame, and for large frames it also reads past the end of the transform buffer. 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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