Vulnpedia
← All CVEs

CVE-2026-100805

HIGH 7.5

Published 2026-09-29 · Last modified 2026-09-30

Race condition, use-after-free in the Audio/Video component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.

ELEVATED IMPACT

Severe if exploited (CVSS 7.5), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 12th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

7.5CVSS 3.1 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ⚠User interaction: A user must take an action (click / open a file)
  • ⚠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-2026-100805/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-2026-100805/poc.json

Affected

Vendors Mozilla

Products Thunderbird Firefox

Weakness (CWE)

  • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
  • CWE-416: Use After Free

CVSS vector

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

Known Affected Software Configurations

VendorProductVersion range
MozillaFirefox< 157.0.0
MozillaThunderbird< 157.0

All CVSS metrics

  • HIGH 7.5 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
  • HIGH 7.5 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS