CVE-2025-1933: mozilla firefox
Vulnerability summary
CVE-2025-1933 is a high (CVSS 7.6) vulnerability in mozilla firefox. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23.3% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 24 · Related 9Timeline
- 04-03-2025PublishedVulnerability first disclosed.
- 04-06-2026Last modifiedVulnerability information updated.
Description
On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
CVSS metrics
6 scores · 6 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.6HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
- OSV · DebianEcosystem advisory · calculated7.6HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
- OSV · WolfiEcosystem advisory · calculated7.6HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
- OSV · ChainguardEcosystem advisory · calculated7.6HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
- NVDNIST7.6HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
EPSS trend
Probability
0.32%
Chance of exploitation in the next 30 days
Percentile
23%
Versus all other CVEs
30-day change
+0.01 pp
From 0.31% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu9 products
- firefox< 136.0+build3-0ubuntu0.20.04.1
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
Chainguard2 products
- firefox< 136-r0
- firefox-esr< 136-r0
Debian2 products
- firefox-esr< 128.8.0esr-1~deb12u1 | < 128.8.0esr-1
- thunderbird< 1:128.8.0esr-1~deb12u1 | < 1:128.8.0esr-1
Mozilla2 products
- firefox< 115.21.0 | < 136.0 | ≥ 116.0, < 128.8.0
- thunderbird< 128.8 | ≥ 129.0, < 136.0
Wolfi1 product
- firefox< 136-r0
5 vendors · 16 products
