CVE-2026-45809Public exploitNetwork attack vectorHinoki check available

Service crash via oversized watcher URI copy

Published Aug 4, 2026 · Updated Aug 4, 2026

Stack overflow in affected OpenSIPS versions before 3.6.6 and 4.0.0-rc1 allows remote attackers to crash a SIP worker. The create_winfo_xml() function in modules/presence/notify.c copies w->uri.len bytes into a 200-byte stack buffer without checking the watcher URI length. Exploitation requires reachable SUBSCRIBE routing with the presence and presence_xml modules loaded, and the verified consequence is a worker crash.

CVSS severity8.7
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stack overflow in affected OpenSIPS versions before 3.6.6 and 4.0.0-rc1 allows remote attackers to crash a SIP worker. The create_winfo_xml() function in modules/presence/notify.c copies w->uri.len bytes into a 200-byte stack buffer without checking the watcher URI length. Exploitation requires reachable SUBSCRIBE routing with the presence and presence_xml modules loaded, and the verified consequence is a worker crash.

The record

CVE
CVE-2026-45809
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
OpenSIPS
Product
OpenSIPS
Classifications
CWE-121, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=>= 3.4.0, < 3.6.6
  2. Affected versionversion=>= 4.0.0-beta, < 4.0.0-rc1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSIPS · OpenSIPSversion=>= 3.4.0, < 3.6.6; version=>= 4.0.0-beta, < 4.0.0-rc1

Published CVSS scores

8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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.

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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 exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1499.004Application or System Exploitation

Public exploit references

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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