Use-after-free in the Audio/Video component
Affects Firefox, with the fix listed in Firefox ESR 115.45. No vendor severity rating is given alongside the CVSS score of 8.8.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in Firefox ESR 115.45
- Who is exposed
- Specific setups only
Do first: Upgrade to a fixed version: Firefox ESR 115.45.
- Published
- 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? →
- 22/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- 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
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox ESR 115.45.
cve.now Index
- Exploitation0/40No signal
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.8/10CVSS 8.8, total technical impact per CISA
- No patch0/5No signal
What would change the score
- Would score about 72 if added to CISA KEV
- Would score about 67 if CISA's SSVC rates exploitation active
What to do
Upgrade to a fixed version: Firefox ESR 115.45.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Mozilla Firefox
Version range not reported
Evidence 2
- Link
- Link
Corrections
None so far.
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Questions about CVE-2026-124952
Is CVE-2026-124952 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
What does this mean?
This is a use-after-free bug in Firefox's Audio/Video component, where memory is used after it has been freed. The advisory rates the impact as high but does not describe further what an attacker could gain.Source: mozilla.org
Am I affected, and how do I check?
The checked facts do not list affected version ranges or required settings. Check the installed Firefox version number and compare it with the fixed version, Firefox ESR 115.45.Source: mozilla.org
How do I fix CVE-2026-124952?
Update to Firefox ESR 115.45 or a later release that includes the fix.Source: mozilla.org