Vulnpedia
← All CVEs

CVE-2026-12318

HIGH 7.3

Published 2026-06-16 · Last modified 2026-06-16

Incorrect boundary conditions in the Libraries component in NSS. This vulnerability was fixed in Firefox 152 and Thunderbird 152.

ELEVATED IMPACT

Severe if exploited (CVSS 7.3), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 18th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

7.3CVSS 3.1 · HIGH

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityLow

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: No special conditions — reliably repeatable

✓ 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-2026-12318/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-2026-12318/poc.json

Affected

Vendors Mozilla

Products Firefox Thunderbird

Weakness (CWE)

  • CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS vector

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

Known Affected Software Configurations

VendorProductVersion range
MozillaFirefox< 152.0.0
MozillaThunderbird< 152.0.0

All CVSS metrics

  • HIGH 7.3 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
  • HIGH 7.3 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS