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CVE-2025-1938

Memory safety bugs fixed in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8

MEDIUM
6.5
CVSS Score
Published: March 4, 2025 at 01:31 PM UTC
Updated: October 5, 2026 at 03:10 PM UTC
2 products affected across 1 vendorFirefoxThunderbird

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Firefox· Mozilla
95%
v < 128.7.0v < 135.0
Affected range stops below 128.7.0, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 128.8 (unaffected)
Affected range stops below 135.0, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 136 (unaffected)
Thunderbird· Mozilla
95%
v < 128.7.0129.0 ≤ v < 135.0
Affected range stops below 128.7.0, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 128.8 (unaffected)
Affected range stops below 135.0, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 136 (unaffected)

References (6)

Issue Tracking
Source: [email protected]
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1922889%2C1935004%2C1943586%2C1943912%2C1948111
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2025-14/
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2025-16/
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2025-17/
Vendor Advisory
Source: [email protected]
https://www.mozilla.org/security/advisories/mfsa2025-18/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-787

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