Incorrect boundary conditions in the Layout: Block and Inline component
Affects Mozilla Firefox; the affected version range is not given. CVSS rates it 8.8 (high), and no vendor severity is given. Fixed in Firefox 159.0.1.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in Firefox 159.0.1
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects Firefox; fixed in Firefox 159.0.1
- Exploitation0/40No signal
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Reach: unknown (data gap). 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
CVE-2026-120572 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.8 (high) and affects Firefox; fixed in Firefox 159.0.1.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- 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
- Fix
- Fixed in Firefox 159.0.1
- 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
This vulnerability affects Mozilla Firefox, a web browser, specifically its Layout component that handles block and inline content rendering. Incorrect boundary checks in this component could allow a malicious web page to cause memory corruption or unexpected browser behavior.
Read the original description
Incorrect boundary conditions in the Layout: Block and Inline component. This vulnerability was fixed in Firefox 159.0.1.
What to do
Check whether your setup matches what the bug needs.
Affects Firefox; fixed in Firefox 159.0.1Upgrade to a fixed version: Firefox 159.0.1.
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.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-120572
Is CVE-2026-120572 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?
The advisory title says the bug is an incorrect boundary condition in Firefox's Layout component for Block and Inline content. The facts do not describe what the flaw does beyond that.Source: mozilla.org
Am I affected, and how do I check?
The facts name Firefox but give no affected version range or setup. To check a installed version, open the menu, choose Help, then About Firefox, and compare the number with 159.0.1.Source: mozilla.org
How do I fix CVE-2026-120572?
Update Firefox to 159.0.1 or later, which is the fixed release named in the advisory.Source: mozilla.org