CVE-2026-0878: mozilla firefox Improper Input Validation
CVSS: 8.0v3.1HighModified
AliasesUBUNTU-CVE-2026-0878DEBIAN-CVE-2026-0878CGA-2rr5-29rx-83qhCGA-rp99-rmgv-g27xCGA-4446-95gc-5fh3CGA-mfmf-9hq6-7q5r
Published 13-01-2026Last modified 15-07-2026
Vulnerability summary
CVE-2026-0878 is a high (CVSS 8.0) Improper Input Validation vulnerability in mozilla firefox. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 39.2% of scored vulnerabilities.
CVSS score
8.0/10
010
High · v3.1 (CVE.org)EPSS score
0.47%
0%100%
Low · -0.01 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 11DLA-4439-1DLA-4442-1DSA-6101-1DSA-6103-1MGASA-2026-0013MGASA-2026-0014OPENSUSE-SU-2026:10037-1OPENSUSE-SU-2026:10046-1OPENSUSE-SU-2026:10058-1OPENSUSE-SU-2026:20041-1OPENSUSE-SU-2026:20391-1RHSA-2026:0667RHSA-2026:0694RHSA-2026:0924RHSA-2026:1320RHSA-2026:1413RHSA-2026:1414RHSA-2026:1415RHSA-2026:1461RHSA-2026:1462RHSA-2026:1471RHSA-2026:1487RHSA-2026:2041RHSA-2026:2043RHSA-2026:2044RHSA-2026:2047RHSA-2026:2069RHSA-2026:2070RHSA-2026:2073RHSA-2026:2074RHSA-2026:2220RHSA-2026:2231RHSA-2026:2271RHSA-2026:2286SUSE-SU-2026:0122-1SUSE-SU-2026:0153-1SUSE-SU-2026:0260-1SUSE-SU-2026:20086-1CGA-RRVF-R3RW-63QWUSN-7991-1
Timeline
- 13-01-2026PublishedVulnerability first disclosed.
- 15-07-2026Last modifiedVulnerability information updated.
Description
Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
CVSS metrics
6 scores · 6 sources · 1 versionHigh 8.0Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:NSources6 sources · 7.5–8.0
- 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 · calculated8.0HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
- OSV · WolfiEcosystem advisory · calculated8.0HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
- OSV · ChainguardEcosystem advisory · calculated8.0HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
- NVDNIST8.0HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
EPSS trend
Probability
0.47%
Chance of exploitation in the next 30 days
Percentile
39%
Versus all other CVEs
30-day change
-0.01 pp
From 0.48% on 20-09-2026
20-09-202620-10-2026
EPSS score0.47%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- 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.
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< 140.7-r0
- firefox-esr< 140.7-r0
Debian2 products
- firefox-esr< 140.7.0esr-1~deb12u1 | < 140.7.0esr-1~deb13u1 | < 140.7.0esr-1
- thunderbird< 1:140.7.0esr-1~deb12u1 | < 1:140.7.0esr-1~deb13u1 | < 1:140.7.0esr-1
Mozilla2 products
- firefox< 140.7.0 | < 147.0
- thunderbird< 140.7.0 | < 147.0
Wolfi1 product
- firefox< 140.7-r0
5 vendors · 15 products
