VulnerabilityPublished 30 Oct 2025Updated 1 Dec 2025

CVE-2025-48980: Brave Desktop Browser · Unvalidated Cookie Trust

Affects Brave Desktop BrowserSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 1.83.10 when convenient.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.0 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.83.10

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Brave Desktop Browser to 1.83.10.

Affected software

Product	Affected	Fixed in
Brave Desktop Browser	Affected =1.83.10 <1.83.10	Fixed in 1.83.10

AI-suggested

The primary mitigation is to upgrade Brave Desktop Browser to version 1.83.10 or later, where the vulnerability is fixed. Organizations should enforce browser update policies to ensure all users apply this patch promptly. If immediate upgrading is not feasible, disabling the split view feature in Brave Browser settings can prevent exploitation by eliminating the flawed context menu behavior. Additionally, organizations should educate users about the risks of opening untrusted links in split view and encourage cautious browsing habits. Implementing network-level protections such as web filtering to block known malicious URLs can reduce exposure. Monitoring browser telemetry and logs for unusual cross-site navigation patterns may help detect exploitation attempts. Finally, organizations should review cookie handling policies and consider additional security controls like multi-factor authentication to mitigate potential session hijacking resulting from cookie leakage.

Description

In Brave Browser Desktop versions prior to 1.83.10 that have the split view feature enabled, the "Open Link in Split View" context menu item did not respect the SameSite cookie attribute. Therefore SameSite=Strict cookies would be sent on a cross-site navigation using this method.

Impact

For European organizations, this vulnerability poses a risk to user privacy and data confidentiality, especially for entities handling sensitive personal information such as financial institutions, healthcare providers, and e-commerce platforms. The unintended transmission of SameSite=Strict cookies during cross-site navigation could lead to session hijacking or unauthorized access to user accounts if attackers can trick users into opening malicious links in split view. This undermines the privacy guarantees that Brave Browser aims to provide, potentially exposing organizations to data protection compliance issues under GDPR. While the vulnerability does not affect system integrity or availability, the confidentiality breach could damage user trust and lead to regulatory penalties. Organizations with employees or customers using vulnerable Brave versions may face increased risk of targeted phishing or social engineering attacks leveraging this flaw. The requirement for user interaction limits mass exploitation but does not eliminate targeted attacks. Overall, the impact is moderate but significant for privacy-conscious European organizations.

CWE-565Reliance on Cookies without Validation and Integrity Checking (opens in a new tab)
Base weaknessOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.
Architecture and Design
Avoid using cookie data for a security-related decision.
Implementation
Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.
Architecture and Design
Add integrity checks to detect tampering.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Access Control (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.1 (opens in a new tab)
V1.5.3 (opens in a new tab)
V4.1.1 (opens in a new tab)
Attack patterns
Session Credential Falsification through Manipulation (opens in a new tab)
Accessing/Intercepting/Modifying HTTP Cookies (opens in a new tab)
Manipulating Opaque Client-based Data Tokens (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

hackerone.com/reports/3253725 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 1 Dec 2025, 21:18 UTC

WeaknessesCWE-565

Technical details

References

Community reviews

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