Apache Lucy: Stack-based Buffer Overflow
CVE-2026-61486 is a critical-severity stack-based buffer overflow vulnerability in Apache Lucy from Apache, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 0.8.0 as the first without the flaw, so updating Apache Lucy to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.81% chance of exploitation within 30 days, higher than 57% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Apache Lucy to 0.8.0 or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Lucy | before 0.8.0 | 0.8.0 |
| Apache | Lucy | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
** UNSUPPORTED WHEN ASSIGNED ** Stack-based Buffer Overflow vulnerability in Apache Lucy. This issue affects Apache Lucy: all versions. As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users. Lucy is now maintained outside of the ASF at https://github.com/lucysearch . This issue has been fixed in 0.8.0 there. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- openwall.com/lists/oss-security/2026/08/05/7Mailing List, Third Party Advisory
Other vulnerabilities in Apache Lucy
- 9.8 Critical severity
- 7.5 High severity
Recent Stack-based Buffer Overflow vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 7.5 High severity
- 8.7 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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