CVE-2026-50161Network attack vector

Heap corruption via wrapped WebSocket length check

Published Aug 18, 2026 · Updated Aug 19, 2026

Integer overflow in websock_decode() in Baresip Foundation libre before 4.8.1 allows remote attackers to corrupt memory via a WebSocket frame. In src/websock/websock.c, the masked-frame check adds 4 to a 64-bit hdr->len without guarding overflow, so a near-UINT64_MAX length wraps, passes mbuf_get_left(), and the XOR unmasking loop writes past the heap buffer. Reachability requires a WebSocket server built on websock_accept() or websock_accept_proto() and only the HTTP upgrade handshake; the published impact is heap corruption or process crash, not a confirmed code-execution path.

CVSS severity9.3
Critical
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in websock_decode() in Baresip Foundation libre before 4.8.1 allows remote attackers to corrupt memory via a WebSocket frame. In src/websock/websock.c, the masked-frame check adds 4 to a 64-bit hdr->len without guarding overflow, so a near-UINT64_MAX length wraps, passes mbuf_get_left(), and the XOR unmasking loop writes past the heap buffer. Reachability requires a WebSocket server built on websock_accept() or websock_accept_proto() and only the HTTP upgrade handshake; the published impact is heap corruption or process crash, not a confirmed code-execution path.

The record

CVE
CVE-2026-50161
Published
Aug 18, 2026
Updated
Aug 19, 2026
Vendor
Baresip Foundation
Product
libre
Classifications
CWE-190, CWE-787, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record 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=< 4.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Baresip Foundation · libreversion=< 4.8.1

Published CVSS scores

9.3CVE ProgramCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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