CVE-2022-26498
Published: 15 April 2022
Summary
CVE-2022-26498 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Digium Asterisk. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 22.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Deeper analysis
CVE-2022-26498 is a resource exhaustion vulnerability in Asterisk through 19.x that occurs when STIR/SHAKEN is enabled. The implementation permits retrieval of arbitrary files instead of restricting downloads to certificates, and these files may be far larger than expected certificates, exhausting memory or other resources on the affected system. The flaw is tracked as CWE-400 and carries a CVSS 3.1 score of 7.5 reflecting high availability impact with network attack vector and no required privileges.
An unauthenticated remote attacker can trigger the flaw by supplying a STIR/SHAKEN identity header that causes Asterisk to fetch an oversized non-certificate file, resulting in denial of service without any user interaction or authentication.
Asterisk Project Security Advisory AST-2022-001 and the associated patches state that the issue is resolved in releases 16.25.2, 18.11.2, and 19.3.2; the fixes are distributed through the official Asterisk downloads site, and Debian has published corresponding updates for its LTS branches.
The EPSS probability rose from a low baseline to a peak of 0.0574 on 2025-01-22 before receding to the current value of 0.0101, indicating that exploitation interest emerged years after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2022-31056
Vulnerability details
An issue was discovered in Asterisk through 19.x. When using STIR/SHAKEN, it is possible to download files that are not certificates. These files could be much larger than what one would expect to download, leading to Resource Exhaustion. This is…
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fixed in 16.25.2, 18.11.2, and 19.3.2.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.