Ning compress-lzf: Out-of-bounds memory access in UnsafeChunkDecoder
Summary
The Java library compress-lzf before version 1.2.0 contains an out-of-bounds memory access in its sun.misc.Unsafe-based UnsafeChunkDecoder, which does not validate back-references and literal runs. An attacker who can supply crafted LZF data to an application using the default LZFDecoder can leak unrelated JVM heap memory into the decompressed output or crash the JVM. No privileges or user interaction are required, but exposure depends on whether the application decompresses untrusted input.
Affected
- ning compress-lzf, versions 0 to before 1.2.0
- Default configuration (the default LZFDecoder uses the affected decoder)
Fixed in
- Upgrade to compress-lzf 1.2.0 or later
Workaround
Unknown.
- Until the upgrade is done, decompress only LZF data from trusted sources.
Exploitation
- CISA SSVC: Exploitation none, Automatable yes, Technical Impact partial.
- Not listed as known exploited in the sources reviewed.
- No public proof of concept found in searches; this is not a full search.
Our recommendation
- Search SBOMs and Maven/Gradle dependency files for compress-lzf, including transitive dependencies.
- Upgrade to version 1.2.0 or later and test the application first, as this is a library change.
- Prioritise applications that decompress LZF data from external parties, such as uploads, API payloads or message queues.
- Monitor the NVD and the GitHub advisory for the final analysis.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- VulnCheck advisory www.vulncheck.com
- Fix commit 06bdc37 github.com
- Pull request #68 github.com
- Vulnerable code UnsafeChunkDecoder.java github.com
- GitHub Security Lab discussion 970 github.com
- ning/compress project README github.com
- VulDB entry vuldb.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 15:41.
Original description (NVD)
Ning compress-lzf before 1.2.0 contains an out-of-bounds memory access vulnerability in the sun.misc.Unsafe based UnsafeChunkDecoder that fails to validate back-references and literal runs. Attackers can supply crafted LZF streams to applications using the default LZFDecoder to leak unrelated JVM heap memory into decompressed output or crash the JVM.
NVD references (6)
- https://github.com/github/securitylab/discussions/970
- https://github.com/ning/compress
- https://github.com/ning/compress/blob/compress-lzf-1.1.3/src/main/java/com/ning/compress/lzf/impl/UnsafeChunk…
- https://github.com/ning/compress/commit/06bdc3744a96b736a7118891f403e44c664f108b
- https://github.com/ning/compress/pull/68
- https://www.vulncheck.com/advisories/ning-compress-lzf-before-1.2.0-out-of-bounds-memory-access-via-unsafechu…
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.