CVE-2021-1501
No exploitation reported by the sources we read.
- Published2021-04-29
- Fixed in9.15.1.15 · 9.14.2.13 · 9.13.1.21 · 9.12.4.18 · 9.9.2.85 · 9.8.4.34
- WeaknessCWE-613
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
A vulnerability in the SIP inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition.The vulnerability is due to a crash that occurs during a hash lookup for a SIP pinhole connection. An attacker could exploit this vulnerability by sending crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a crash and reload of the affected device.
Timeline
dates in UTC- 2021-04-2918:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-1501?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-1501?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 9.15 | ≥ 9.15, < 9.15.1.15 | 9.15.1.15 | NVD |
| 9.14 | ≥ 9.14, < 9.14.2.13 | 9.14.2.13 | NVD |
| 9.13 | ≥ 9.13, < 9.13.1.21 | 9.13.1.21 | NVD |
| 9.x | ≥ 9.10, < 9.12.4.18 | 9.12.4.18 | NVD |
| 9.9 | ≥ 9.9, < 9.9.2.85 | 9.9.2.85 | NVD |
| 9.8 | ≥ 9.8, < 9.8.4.34 | 9.8.4.34 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 6.7 | ≥ 6.7.0, < 6.7.0.2 | 6.7.0.2 | NVD |
| 6.x | ≥ 6.5.0, < 6.6.4 | 6.6.4 | NVD |
| 6.x | ≥ 6.2.2, < 6.4.0.12 | 6.4.0.12 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Cisco ASA to 9.15.1.15 · 9.14.2.13 · 9.13.1.21 · 9.12.4.18 · 9.9.2.85 · 9.8.4.34
Advisories and patches
- tools.cisco.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2021-04-29
- Last Modified
- 2026-08-11
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-1501?
Is CVE-2021-1501 actively exploited?
What is the CVSS score for CVE-2021-1501?
Hear about the next vulnerability in your software
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.