CVE-2025-4082 [Medium] | Out-of-bounds Read in Firefox

Modification of specific WebGL shader attributes could trigger an out-of-bounds read, which, when chained with other vulnerabilities, could be used to escalate privileges. *This bug only affects Thunderbird for macOS. Other versions of Thunderbird are unaffected.*. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-26	0.40%	0.34%	-0.07%
2	2026-02-23	0.06%	0.40%	+0.34%
3	2025-12-12	—	0.06%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-26

0.40%

0.34%

-0.07%

2026-02-23

0.06%

0.40%

+0.34%

2025-12-12

—

0.06%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.9	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	2.2	3.6	134c704f-9b21-4f2e-91b3-4a467353bcc0

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.9

3.1

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

2.2

3.6

134c704f-9b21-4f2e-91b3-4a467353bcc0

OS Trackers for CVE-2025-4082

vendor	priority	summary	link
`alpine`	—	CVE-2025-4082: 3 source package rows (firefox, firefox-esr, thunderbird); 353 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 353.	https://security.alpinelinux.org/vuln/CVE-2025-4082
`debian`	unimportant	CVE-2025-4082 unimportant priority: Debian including 3 source packages (firefox, firefox-esr, thunderbird), 11 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 11.	https://security-tracker.debian.org/tracker/CVE-2025-4082
`redhat`	high	—	https://access.redhat.com/security/cve/CVE-2025-4082
`suse`	high	CVE-2025-4082 severity important: SUSE including 18 source package names (MozillaFirefox-128.10.0-150200.152.179.1, MozillaFirefox-138.0-1.1, …), 100 product×package rows across 36 product lines (Container suse/kiosk/firefox-esr, Image SLES15-SP3-SAP-Azure-LI-BYOS-Production, … (36 product lines)): Fixed 100.	https://www.suse.com/security/cve/CVE-2025-4082/
`ubuntu`	medium	CVE-2025-4082 medium priority: Ubuntu including 2 source packages (firefox, thunderbird), 12 status rows across 6 suites (focal, jammy, noble, oracular, plucky, upstream): not-affected 9, DNE 2, needs-triage 1.	https://ubuntu.com/security/CVE-2025-4082

Affected software / configurations for CVE-2025-4082

Vendor	Product	Version	Raw CPE
mozilla	firefox	< 115.23	cpe:2.3:a:mozilla:firefox:::::esr:::*
mozilla	firefox	< 138.0	cpe:2.3:a:mozilla:firefox:::::-:::*
mozilla	firefox	>= 128.0, < 128.10	cpe:2.3:a:mozilla:firefox:::::esr:::*
mozilla	thunderbird	< 128.10.0	cpe:2.3:a:mozilla:thunderbird:::::esr:::*
mozilla	thunderbird	< 138.0	cpe:2.3:a:mozilla:thunderbird:::::-:::*

References for CVE-2025-4082

URL	Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1937097	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2025-28/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-29/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-30/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-31/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-32/	Vendor Advisory
https://lists.debian.org/debian-lts-announce/2025/05/msg00022.html

URL

CVE-2025-4082 | WebGL shader attribute memory corruption in Thunderbird for macOS

Exploit prediction scoring system (EPSS) score for CVE-2025-4082

Common vulnerability scoring system (CVSS) metrics for CVE-2025-4082

Weakness enumeration for CVE-2025-4082

OS Trackers for CVE-2025-4082

Affected software / configurations for CVE-2025-4082

References for CVE-2025-4082