CVE-2025-15570
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Use-After-Free in lrzip lzma_decompress_buf Allows Local Exploit

Publication date: 2026-02-10

Last updated on: 2026-05-06

Assigner: VulDB

Description
A vulnerability was found in ckolivas lrzip up to 0.651. This impacts the function lzma_decompress_buf of the file stream.c. Performing a manipulation results in use after free. Attacking locally is a requirement. The exploit has been made public and could be used. The project was informed of the problem early through an issue report but has not responded yet.
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Meta Information
Published
2026-02-10
Last Modified
2026-05-06
Generated
2026-06-16
AI Q&A
2026-02-10
EPSS Evaluated
2026-06-15
NVD
CVE-2025-15570
EUVD
EUVD-2025-207358
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
ckolivas lrzip to 0.651 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-119 The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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Executive Summary

CVE-2025-15570 is a concurrency-related use-after-free (UAF) vulnerability in the lrzip compression tool, specifically affecting the function lzma_decompress_buf in the file stream.c. The issue arises because the memory pointed to by sinfo->ucthreads can be freed by the function clear_rulist while it is still being accessed concurrently by lzma_decompress_buf, leading to a race condition.

This race condition causes heap memory corruption due to unsynchronized access and deallocation of shared memory in a multithreaded environment. The vulnerability can be triggered locally by running lrzip with a specially crafted proof-of-concept file.

The use-after-free flaw means that the program attempts to use memory after it has been freed, which can lead to crashes, unexpected behavior, or potentially arbitrary code execution.

Impact Analysis

Exploitation of this vulnerability can lead to memory corruption, which may cause program crashes or allow an attacker to execute arbitrary commands on the affected system.

Since the vulnerability requires local access to exploit, an attacker with local privileges could leverage this flaw to escalate privileges or compromise system integrity.

The impact affects confidentiality, integrity, and availability of the system running the vulnerable lrzip version, potentially leading to unauthorized access or denial of service.

Compliance Impact

I don't know

Detection Guidance

This vulnerability can be detected by running the lrzip tool with a crafted proof-of-concept (PoC) file that triggers the use-after-free condition. The PoC file is publicly available and can be used to reproduce the bug reliably.

A suggested command to detect the vulnerability is to run lrzip in test mode with multithreading enabled, using the PoC file:

  • ./lrzip -t -p2 ./PoC_UAF

Additionally, reproducing the bug and detecting the use-after-free can be facilitated by using debugging tools such as AddressSanitizer (ASAN) to catch heap-use-after-free errors during execution.

Mitigation Strategies

Currently, no official fix or response has been provided by the lrzip project maintainers for this vulnerability.

Immediate mitigation steps include:

  • Avoid running lrzip version 0.651 or earlier on systems where local users could exploit this vulnerability.
  • Consider restricting local access to systems using lrzip to trusted users only.
  • Monitor for updates or patches from the lrzip project or consider using alternative compression tools until a fix is released.
  • If possible, disable multithreading in lrzip (e.g., using the `-p 1` option) to reduce concurrency risks, although this is not guaranteed to fully mitigate the issue.
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