CVE-2026-8947: mozilla firefox Use After Free
CVSS: 7.3v3.1HighModified
AliasesUBUNTU-CVE-2026-8947DEBIAN-CVE-2026-8947CGA-f3cr-v6j5-3pr8CGA-wphf-xmjg-c464CGA-7f9c-m28g-h47hCGA-mv4h-r227-5cp5
Published 19-05-2026Last modified 15-07-2026
Vulnerability summary
CVE-2026-8947 is a high (CVSS 7.3) Use After Free vulnerability in mozilla firefox. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 37.3% of scored vulnerabilities.
CVSS score
7.3/10
010
High · v3.1 (CVE.org)EPSS score
0.45%
0%100%
Low · +0.03 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 27 · Related 5MGASA-2026-0164MGASA-2026-0165OPENSUSE-SU-2026:10813-1OPENSUSE-SU-2026:10863-1OPENSUSE-SU-2026:10864-1OPENSUSE-SU-2026:21168-1RHSA-2026:21378RHSA-2026:21380RHSA-2026:21381RHSA-2026:21382RHSA-2026:22325RHSA-2026:22643RHSA-2026:26174RHSA-2026:26268RHSA-2026:26269RHSA-2026:26270RHSA-2026:26491RHSA-2026:26492RHSA-2026:26493RHSA-2026:26521RHSA-2026:26536RHSA-2026:26539RHSA-2026:26551RHSA-2026:26606RHSA-2026:26629RHSA-2026:26630RHSA-2026:27715CGA-2FHV-XGC3-3PPC
Timeline
- 19-05-2026PublishedVulnerability first disclosed.
- 15-07-2026Last modifiedVulnerability information updated.
Description
Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
CVSS metrics
4 scores · 4 sources · 1 versionHigh 7.3Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:LSources4 sources · 7.3–7.5
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HDiffers
- OSV · DebianEcosystem advisory · calculated7.3HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- NVDNIST7.3HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS trend
Probability
0.45%
Chance of exploitation in the next 30 days
Percentile
37%
Versus all other CVEs
30-day change
+0.03 pp
From 0.41% on 19-09-2026
19-09-202619-10-2026
EPSS score0.45%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
- 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)
Chainguard2 products
- firefox< 151.0.1-r0
- firefox-esr< 140.11.0-r0
Debian2 products
- firefox-esr< 140.11.0esr-1~deb12u1 | < 140.11.0esr-1~deb13u1 | < 140.11.0esr-1
- thunderbird< 1:140.11.0esr-1~deb12u1 | < 1:140.11.0esr-1~deb13u1 | < 1:140.11.0esr-1
Mozilla2 products
- firefox< 115.36.0 | < 151.0.0 | ≥ 140.0, < 140.11.0
- thunderbird< 140.11
Wolfi1 product
- firefox< 151.0.1-r0
5 vendors · 15 products
