November 13, 2026

CVE Watchtower

CVE-2026-124959Out-of-bounds Write

NVDCVSS scored by 134c704f-9b21-4f2e-91b3-4a467353bcc0

Vulnerability Summary

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.
Severity Level
HIGH(7.1)
Published Date
Nov 9, 2026
Last Modified
Nov 12, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.13%Probability
Root Weakness (CWE)
CWE-787: Out-of-bounds Write β†—
The product writes data past the end, or before the beginning, of the intended buffer.
CVSS v3.1 Base Metrics — Score 7.1 (HIGH)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
Attack VectorLocal
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged
ConfidentialityNone
IntegrityHigh
AvailabilityHigh

Affected & Patched Versions

Affected Versions
Not provided by NVD for this CVE.
Patched Versions
No patched version published yet
Until a fix ships, reduce exposure:
  • Restrict access to the affected service or interface to trusted networks.
  • Disable the affected feature if you do not need it.
  • Watch the vendor advisory for a firmware or software update.

What to do

Plan remediation soon. No exploitation is confirmed yet, but the severity is high.

  1. Check whether you run the affected product and which version.
  2. No patched version is listed yet. Limit access to the affected service to trusted networks, and disable the feature if you can.
  3. Subscribe to the vendor advisory so you learn when a fix ships.

Timeline

  • Nov 9, 2026Published
  • Nov 12, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 13, 2026 19:14 UTC