CVE-2026-16353: mozilla firefox Use After Free
CVSS: 9.8v3.1CriticalAnalyzed
AliasesUBUNTU-CVE-2026-16353DEBIAN-CVE-2026-16353CGA-6fjv-x2gf-gph9CGA-6v4w-8jjf-49vwCGA-9p43-9xvh-p8v2CGA-f238-vq65-cv2xCGA-3g99-p85m-rcmcCGA-f87p-cfjf-62x3CGA-qc8r-872h-hc2qCGA-v3q6-9pjj-v9w8
Published 21-07-2026Last modified 22-07-2026
Vulnerability summary
CVE-2026-16353 is a critical (CVSS 9.8) Use After Free vulnerability in mozilla firefox. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 42.7% of scored vulnerabilities.
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)EPSS score
0.52%
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 38 · Related 16MGASA-2026-0325MGASA-2026-0326OPENSUSE-SU-2026:11329-1OPENSUSE-SU-2026:11358-1OPENSUSE-SU-2026:11359-1OPENSUSE-SU-2026:21519-1OPENSUSE-SU-2026:21713-1RHSA-2026:47101RHSA-2026:47104RHSA-2026:47105RHSA-2026:49621RHSA-2026:49921RHSA-2026:49922RHSA-2026:53444RHSA-2026:53445RHSA-2026:53446RHSA-2026:53453RHSA-2026:53454RHSA-2026:53455RHSA-2026:53475RHSA-2026:54180RHSA-2026:54181RHSA-2026:54182RHSA-2026:54185RHSA-2026:54248RHSA-2026:54249RHSA-2026:54259RHSA-2026:54339SUSE-SU-2026:23115-1SUSE-SU-2026:23137-1SUSE-SU-2026:23411-1SUSE-SU-2026:23590-1SUSE-SU-2026:3200-1SUSE-SU-2026:3221-1SUSE-SU-2026:3546-1SUSE-SU-2026:4140-1SUSE-SU-2026:4156-1SUSE-SU-2026:4268-1CGA-WM6V-548Q-3WHG
Timeline
- 21-07-2026PublishedVulnerability first disclosed.
- 22-07-2026Last modifiedVulnerability information updated.
Description
Invalid pointer in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
CVSS metrics
4 scores · 4 sources · 1 versionCritical 9.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 4 agree
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.52%
Chance of exploitation in the next 30 days
Percentile
43%
Versus all other CVEs
30-day change
0.00 pp
From 0.52% on 19-09-2026
19-09-202619-10-2026
EPSS score0.52%
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-476NULL Pointer DereferenceThe product dereferences a pointer that it expects to be valid but is NULL.
- CWE-824Access of Uninitialized PointerThe product accesses or uses a pointer that has not been initialized.
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)
Chainguard4 products
- firefox< 153.0-r0
- firefox-docker-selenium-compat< 153.0-r0
- firefox-esr< 153.0-r0 | < 153.0-r1
- firefox-esr-140< 140.13.0-r0
Debian2 products
- firefox-esr< 140.13.0esr-1~deb12u1 | < 140.13.0esr-1~deb13u1 | < 140.13.0esr-1
- thunderbird< 1:140.13.0esr-2~deb12u1 | < 1:140.13.0esr-2~deb13u1 | < 1:140.13.0esr-1
Mozilla2 products
- firefox< 115.38.0 | < 153.0.0 | ≥ 128.1.0, < 140.13.0
- thunderbird< 140.13.0 | ≥ 141.0, < 153.0
Wolfi2 products
- firefox< 153.0-r0
- firefox-docker-selenium-compat< 153.0-r0
5 vendors · 18 products
References
11 links- bugzilla.mozilla.org/show_bug.cgi?id=2049523Permissions Required
- www.mozilla.org/security/advisories/mfsa2026-68/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-69/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-70/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-71/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-72/Vendor Advisory
