- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 5/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The loadIndex function in the nmslib hnswlib and Spotify Voyager HNSW index libraries fails to check that the element count in a serialized index fits within its stored capacity, so a crafted index file can cause a heap out-of-bounds write that may crash the application when loaded. Because the access vector and login requirements are not specified, this description does not state how an attacker would reach the flaw.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
The loadIndex function in nmslib hnswlib and Spotify Voyager does not verify that the element count in a serialized HNSW index is within the stored capacity used to allocate the heap buffer. An attacker can supply a crafted index file with an element count greater than the stored capacity, causing the loader to write beyond the allocated buffer and potentially crash the application when it loads the file.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity?/10Unknown. No CVSS score or vendor rating
- No patch5/5No patch listed yet
What would change the score
- Would score about 60 if added to CISA KEV
- Would score about 55 if CISA's SSVC rates exploitation active
- Would score about 27 if advisories confirm default setups are exposed
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Spotify Voyager
From 2.0.7 · through 2.1.1
- hnswlib hnswlib
From 0.5.0 · through 0.9.0
Evidence 3
- Repository
- Repository
- Link
Corrections
None so far.
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Questions about CVE-2026-124959
Is CVE-2026-124959 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-124959?
Voyager: from 2.0.7 through 2.1.1. hnswlib: from 0.5.0 through 0.9.0.Source: cve.now feed data