CVE-2026-61485 Overview
CVE-2026-61485 is a memory allocation vulnerability affecting all versions of Apache Lucy, a full-text search engine library. The flaw falls under [CWE-789: Memory Allocation with Excessive Size Value], allowing a remote attacker to trigger allocation of unreasonably large memory regions. Successful exploitation leads to resource exhaustion and denial of service against the host process.
Apache Lucy is a retired project. The Apache Software Foundation has stated it will not release a fix. Users must migrate to an alternative search library or restrict network access to trusted users only.
Critical Impact
Remote, unauthenticated attackers can exhaust process memory and cause denial of service. No patch will be released because Apache Lucy is end-of-life.
Affected Products
- Apache Lucy — all versions
- Applications embedding Apache Lucy as a search backend
- Services exposing Apache Lucy query interfaces to untrusted network input
Discovery Timeline
- 2026-08-05 - CVE-2026-61485 published to NVD
- 2026-08-05 - Apache Software Foundation publishes advisory on the Apache Mailing List Discussion and Openwall OSS Security Update
- 2026-08-05 - Last updated in NVD database
Technical Details for CVE-2026-61485
Vulnerability Analysis
The vulnerability is classified under [CWE-789: Memory Allocation with Excessive Size Value]. Apache Lucy allocates memory using size values derived from attacker-controllable input without enforcing an upper bound. When the input specifies a very large size, the library requests a correspondingly large allocation from the operating system.
The resulting allocation depletes available memory on the host. The process either crashes on allocation failure or is terminated by the operating system's out-of-memory killer. The impact profile targets availability only; confidentiality and integrity are not affected.
Because Apache Lucy is retired, the maintainers will not ship a code fix. The advisory instructs users to migrate away from Lucy or place it behind strict access controls.
Root Cause
The root cause is missing validation of size fields that drive memory allocation calls inside Apache Lucy. The library trusts size or length values parsed from external data structures such as index files, query inputs, or serialized objects. No sanity check compares the requested size against available memory or a hard-coded ceiling before the allocation proceeds.
Attack Vector
The attack vector is network-based and requires no authentication or user interaction. An attacker submits a crafted request or file to a service that routes data into Apache Lucy. The malformed input carries an inflated size field. Apache Lucy attempts to satisfy the allocation and consumes memory until the process fails.
Repeated requests amplify the effect and can take down clustered search nodes. Because Apache Lucy runs inside a hosting application, that application also crashes when Lucy exhausts its address space.
No verified proof-of-concept code is published in the referenced advisories. Refer to the Apache Mailing List Discussion for further technical context.
Detection Methods for CVE-2026-61485
Indicators of Compromise
- Process crashes or restarts in applications embedding Apache Lucy, correlated with out-of-memory kernel messages such as oom-killer entries in dmesg or /var/log/syslog.
- Sudden spikes in resident set size (RSS) or virtual memory usage of the Lucy-hosting process without a corresponding increase in legitimate query volume.
- Inbound requests containing abnormally large length or count fields directed at Lucy-backed search endpoints.
Detection Strategies
- Monitor process-level memory metrics for services using Apache Lucy and alert on rapid growth exceeding baseline.
- Inspect application logs for repeated malloc failures, std::bad_alloc exceptions, or Lucy runtime errors preceding process termination.
- Deploy web application firewall rules that flag requests with oversized numeric parameters targeting search endpoints.
Monitoring Recommendations
- Enable kernel OOM logging and forward dmesg output to a central log store for correlation with request telemetry.
- Track HTTP request sizes and query complexity on any endpoint reachable by Lucy, alerting on statistical outliers.
- Enforce cgroup or container memory limits so that a single crash is contained and observable rather than cascading.
How to Mitigate CVE-2026-61485
Immediate Actions Required
- Inventory all systems that embed or expose Apache Lucy and mark them for migration; Lucy is retired and will receive no security fixes.
- Restrict network access to Lucy-backed services so that only trusted, authenticated users can submit queries or index data.
- Enforce hard memory limits on the hosting process using ulimit, systemd MemoryMax, or container resource limits.
Patch Information
No patch will be released. The Apache Software Foundation confirmed on the Openwall OSS Security Update that Apache Lucy is retired. Users are advised to migrate to a supported alternative such as Apache Lucene or another maintained search library.
Workarounds
- Place Apache Lucy behind an authenticated reverse proxy and reject requests from untrusted sources.
- Apply input validation at the application layer to cap the size of fields that reach Lucy allocation paths.
- Run Lucy inside a resource-constrained container so an out-of-memory event isolates the failure and enables automatic restart.
- Migrate search functionality to a supported project and decommission Lucy instances once cutover completes.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
