CVE-2025-10148

predictable WebSocket mask

MEDIUM
5.3
CVSS Score
Published: September 12, 2025 at 05:10 AM UTC
Updated: October 19, 2026 at 05:10 PM UTC
1 product affected across 1 vendorCurl

Using curl by curl?

Get instant alerts when new vulnerabilities affect curl - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM5.3
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

curl's websocket code did not update the 32 bit mask pattern for each new outgoing frame as the specification says. Instead it used a fixed mask that persisted and was used throughout the entire connection. A predictable mask pattern allows for a malicious server to induce traffic between the two communicating parties that could be interpreted by an involved proxy (configured or transparent) as genuine, real, HTTP traffic with content and thereby poison its cache. That cached poisoned content could then be served to all users of that proxy.

Affected

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

All versions8.11.0 ≤ v < 8.16.08.11.08.11.18.12.08.12.18.13.08.14.08.14.18.15.0d78e129d50b2d190f1c1bde2ad1f62f02f152db0
Vendor states this is fixed in 84db7a9eae8468c0445b15aa806fa7fa806fa0f2 (fixed)
Affected range stops below 8.14.2, so it looks safe — our inference, not a vendor statement
Affected range stops below 8.16.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (6)

PatchVendor Advisory
Source: 2499f714-1537-4658-8207-48ae4bb9eae9
https://curl.se/docs/CVE-2025-10148.html
Vendor Advisory
Source: 2499f714-1537-4658-8207-48ae4bb9eae9
https://curl.se/docs/CVE-2025-10148.json
Issue TrackingThird Party Advisory
Source: 2499f714-1537-4658-8207-48ae4bb9eae9
https://hackerone.com/reports/3330839
Mailing ListPatchThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2025/09/10/2
Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2025/09/10/3
Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2025/09/10/4

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

5.3MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-340NVD-CWE-noinfo

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card