CVE-2025-10148: predictable WebSocket mask
Vulnerability summary
CVE-2025-10148 is a medium (CVSS 5.3) vulnerability in curl. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 44.5% of scored vulnerabilities.
Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 12 · Related 11Timeline
- 12-09-2025PublishedVulnerability first disclosed.
- 15-09-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 5 sources · 1 version- OSV · AlpineEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS trend
Probability
0.52%
Chance of exploitation in the next 30 days
Percentile
45%
Versus all other CVEs
30-day change
Increase +0.03 pp
From 0.50% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Alpine1 product
- curl≥ 8.11.0, < 8.14.1-r2 | ≥ 8.11.0, < 8.16.0-r0
Curl1 product
- curl≥ 8.11.0, < 8.14.2 | ≥ 8.15.0, < 8.16.0 | ≥ d78e129d50b2d190f1c1bde2ad1f62f02f152db0, < 84db7a9eae8468c0445b15aa806fa7fa806fa0f2 | 8.15.0 | 8.14.1 | 8.14.0 | 8.13.0 | 8.12.1 | 8.12.0 | 8.11.1 | 8.11.0
Debian1 product
- curl< 7.88.1-10+deb12u15 | < 8.14.1-2+deb13u1 | < 8.16.0-1
Haxx1 product
- curl≥ 8.11.0, < 8.16.0
Ubuntu1 product
- curl< 8.5.0-2ubuntu10.7 | < 8.14.1-2ubuntu1.1
5 vendors · 5 products
References
12 links- curl.se/docs/CVE-2025-10148.jsonVendor Advisory
