Summary
Use After Free vulnerability in Apache Arrow C++.
This issue affects Apache Arrow C++ from 15.0.0 through 23.0.0. It can be triggered when reading an Arrow IPC file (but not an IPC stream) with pre-buffering enabled, if the IPC file contains data with variadic buffers (such as Binary View and String View data). Depending on the number of variadic buffers in a record batch column and on the temporal sequence of multi-threaded IO, a write to a dangling pointer could occur. The value (a std::shared_ptr<Buffer> object) that is written to the dangling pointer is not under direct control of the attacker.
Pre-buffering is disabled by default but can be enabled using a specific C++ API call (RecordBatchFileReader::PreBufferMetadata). The functionality is not exposed in language bindings (Python, Ruby, C GLib), so these bindings are not vulnerable.
The most likely consequence of this issue would be random crashes or memory corruption when reading specific kinds of IPC files. If the application allows ingesting IPC files from untrusted sources, this could plausibly be exploited for denial of service. Inducing more targeted kinds of misbehavior (such as confidential data extraction from the running process) depends on memory allocation and multi-threaded IO temporal patterns that are unlikely to be easily controlled by an attacker.
Advice for users of Arrow C++:
check whether you enable pre-buffering on the IPC file reader (using
RecordBatchFileReader::PreBufferMetadata)if so, either disable pre-buffering (which may have adverse performance consequences), or switch to Arrow 23.0.1 which is not vulnerable
Impact
Memory is accessed after it has been freed, leading to undefined behavior in native code. Typical impact: memory corruption, crash, or potential code execution.
CVE-2026-25087 has a CVSS score of 7.0 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (23.0.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-25087? CVE-2026-25087 is a high-severity use after free vulnerability in pyarrow (pip), affecting versions >= 15.0.0, < 23.0.1. It is fixed in 23.0.1. Memory is accessed after it has been freed, leading to undefined behavior in native code.
- How severe is CVE-2026-25087? CVE-2026-25087 has a CVSS score of 7.0 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pyarrow are affected by CVE-2026-25087? pyarrow (pip) versions >= 15.0.0, < 23.0.1 is affected.
- Is there a fix for CVE-2026-25087? Yes. CVE-2026-25087 is fixed in 23.0.1. Upgrade to this version or later.
- Is CVE-2026-25087 exploitable, and should I be worried? Whether CVE-2026-25087 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-25087 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-25087? Upgrade
pyarrowto 23.0.1 or later.