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CVE-2025-8037

26
FAUCET Score

CVE-2025-8037 describes a critical vulnerability in Mozilla Firefox and Thunderbird versions prior to 141 and 140.1, respectively, where a nameless cookie containing an equals sign in its value could shadow other cookies, even secure ones. This vulnerability carries a CVSS score of 9.1 (CRITICAL), indicating it can be exploited remotely with low complexity to achieve high confidentiality and integrity impacts without user interaction. While there is no evidence of active exploitation, public exploit code, or inclusion in CISA's KEV catalog, the vulnerability has garnered some community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
< 140.1CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
< 141.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
< 140.1CPE matchmatch criteria
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
< 141.0CPE matchmatch criteria
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.1CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.22%
Probability of exploitation in next 30 days
EPSS Percentile
12.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0022 is in the 0th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2025-8037Moderate

firefox: thunderbird: Nameless cookies shadow secure cookies

Jul 22, 2025

References

bugzilla.mozilla.org / show_bug.cgi
Permissions Required
mozilla.org / security/advisories/mfsa2025-56
Vendor Advisory
mozilla.org / security/advisories/mfsa2025-59
Vendor Advisory
mozilla.org / security/advisories/mfsa2025-61
Vendor Advisory
mozilla.org / security/advisories/mfsa2025-63
Vendor Advisory