CVE-2025-10148Network attack vector

Proxy cache poisoning via reused WebSocket mask

Published Sep 12, 2025 · Updated Nov 18, 2025

Predictable WebSocket masking in curl 8.11.0 through 8.15.0 allows remote attackers to poison shared proxy caches over cleartext WS. The WebSocket encoder generated a 32-bit mask when accepting the connection, then reused it for every outgoing frame instead of calling Curl_rand for each frame. Exploitation requires a malicious server, ws:// traffic, and a defective intermediary proxy that mistakes framed data for HTTP; poisoned content can then reach every proxy user.

CVSS severity5.3
Medium
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Predictable WebSocket masking in curl 8.11.0 through 8.15.0 allows remote attackers to poison shared proxy caches over cleartext WS. The WebSocket encoder generated a 32-bit mask when accepting the connection, then reused it for every outgoing frame instead of calling Curl_rand for each frame. Exploitation requires a malicious server, ws:// traffic, and a defective intermediary proxy that mistakes framed data for HTTP; poisoned content can then reach every proxy user.

The record

CVE
CVE-2025-10148
Published
Sep 12, 2025
Updated
Nov 18, 2025
Vendor
curl
Product
curl
Classifications
CWE-340
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 18, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.11.0 <=8.11.0
  2. Affected versionversion=8.11.1 <=8.11.1
  3. Affected versionversion=8.12.0 <=8.12.0
  4. Affected versionversion=8.12.1 <=8.12.1
  5. Affected versionversion=8.13.0 <=8.13.0
  6. Affected versionversion=8.14.0 <=8.14.0
  7. Affected versionversion=8.14.1 <=8.14.1
  8. Affected versionversion=8.15.0 <=8.15.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=8.11.0 <=8.11.0; version=8.11.1 <=8.11.1; version=8.12.0 <=8.12.0; version=8.12.1 <=8.12.1; version=8.13.0 <=8.13.0; version=8.14.0 <=8.14.0; version=8.14.1 <=8.14.1; version=8.15.0 <=8.15.0

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-340Generation of Predictable Numbers or Identifiers

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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