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CVE-2026-86871

MEDIUM 5.9

Published 2026-10-20 · Last modified 2026-10-20

An integer underflow was addressed with improved input validation. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. An attacker with control of a network file server may be able to cause unexpected system termination.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 6th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

5.9CVSS 3.1 · MEDIUM

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ⚠Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-86871/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-86871/poc.json

Affected

Vendors Apple

Products Macos

Weakness (CWE)

  • CWE-190: Integer Overflow or Wraparound
  • CWE-20: Improper Input Validation

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

All CVSS metrics

  • MEDIUM 5.9 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  • MEDIUM 5.9 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Technical & other

Sources: NVD · CVE.org · EPSS