CVE-2026-12326: mozilla firefox
CVSS: 8.1v3.1HighModified
AliasesUBUNTU-CVE-2026-12326CGA-8r23-qmr9-62jxCGA-rmff-2xc7-ffv2
Published 16-06-2026Last modified 15-07-2026
Vulnerability summary
CVE-2026-12326 is a high (CVSS 8.1) vulnerability in mozilla firefox. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 28.8% of scored vulnerabilities.
CVSS score
8.1/10
010
High · v3.1 (CVE.org)EPSS score
0.36%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 2 · Related 3Timeline
- 16-06-2026PublishedVulnerability first disclosed.
- 15-07-2026Last modifiedVulnerability information updated.
Description
Memory safety bugs present in Firefox 151 and Thunderbird 151. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 152 and Thunderbird 152.
CVSS metrics
3 scores · 3 sources · 1 versionHigh 8.1Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HSources3 sources · 7.5–8.1
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HDiffers
- NVDNIST8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.36%
Chance of exploitation in the next 30 days
Percentile
29%
Versus all other CVEs
30-day change
0.00 pp
From 0.36% on 21-09-2026
21-09-202621-10-2026
EPSS score0.36%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
- CWE-825Expired Pointer DereferenceThe product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.
Affected systems
Ubuntu8 products
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
Mozilla2 products
- firefox< 152.0.0
- thunderbird< 152.0.0
Chainguard1 product
- firefox< 152-r0
Wolfi1 product
- firefox< 152-r0
4 vendors · 12 products
References
11 links- bugzilla.mozilla.org/buglist.cgiBroken Link
- bugzilla.mozilla.org/buglist.cgiBroken Link
- bugzilla.mozilla.org/buglist.cgiBroken Link
- www.mozilla.org/security/advisories/mfsa2026-57/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-60/Vendor Advisory