CVE-2025-49832Public exploitNetwork attack vector

Service crash via missing Identity header delimiter

Published Aug 1, 2025 · Updated Aug 1, 2025

NULL pointer dereference in affected Asterisk releases allows remote authenticated users to crash the service via a malformed SIP Identity header. In ast_stir_shaken_vs_verify(), strchr() can return NULL when the Identity header lacks a semicolon, but verification.c subtracts that pointer from the header and uses the invalid length for allocation and copying. The endpoint must allow an attacker-controlled Identity header and have STIR/SHAKEN verification enabled in its SIP profile; exploitation crashes the Asterisk process and interrupts telephony service.

CVSS severity6.5
Medium
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in affected Asterisk releases allows remote authenticated users to crash the service via a malformed SIP Identity header. In ast_stir_shaken_vs_verify(), strchr() can return NULL when the Identity header lacks a semicolon, but verification.c subtracts that pointer from the header and uses the invalid length for allocation and copying. The endpoint must allow an attacker-controlled Identity header and have STIR/SHAKEN verification enabled in its SIP profile; exploitation crashes the Asterisk process and interrupts telephony service.

The record

CVE
CVE-2025-49832
Published
Aug 1, 2025
Updated
Aug 1, 2025
Vendor
Asterisk
Product
Asterisk
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 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=< 18.26.3
  2. Affected versionversion=>= 20.00.0, < 20.15.1
  3. Affected versionversion=>= 20.7-cert6, < 20.7-cert7
  4. Affected versionversion=>= 21.00.0, < 21.10.1
  5. Affected versionversion=>= 22.00.0, < 22.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Asterisk · Asteriskversion=< 18.26.3; version=>= 20.00.0, < 20.15.1; version=>= 20.7-cert6, < 20.7-cert7; version=>= 21.00.0, < 21.10.1; version=>= 22.00.0, < 22.5.1

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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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