How severe is CVE-2021-1353?

CVE-2021-1353 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2021-1353 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1353?

CVE-2021-1353 primarily affects Cisco Staros. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-1353?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-1353 published?

CVE-2021-1353 was published on 2021-01-20 and last updated on 2026-06-17.

CVE-2021-1353

CVE-2021-1353 is a medium-severity vulnerability in Cisco Staros with a CVSS 3.x base score of 5.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-401.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
CVSS v2: 5.0
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-401
Affected product: Cisco Staros
Published: 2021-01-20
Last modified: 2026-06-17

Description

A vulnerability in the IPv4 protocol handling of Cisco StarOS could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory leak that occurs during packet processing. An attacker could exploit this vulnerability by sending a series of crafted IPv4 packets through an affected device. A successful exploit could allow the attacker to exhaust the available memory and cause an unexpected restart of the npusim process, leading to a DoS condition on the affected device.

Frequently asked questions

What is CVE-2021-1353?: A vulnerability in the IPv4 protocol handling of Cisco StarOS could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory leak that occurs during packet processing. An attacker could exploit this vulnerability by sending a series of crafted IPv4 packets through an affected device. A successful exploit could allow the attacker to exhaust the available memory and cause an unexpected restart of the npusim process, leading to a DoS condition on the affected device.
How severe is CVE-2021-1353?: CVE-2021-1353 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2021-1353 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1353?: CVE-2021-1353 primarily affects Cisco Staros. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1353?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1353 published?: CVE-2021-1353 was published on 2021-01-20 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr-mem-leak-dos-MTWGHKk3

Affected products (2)

cpe:2.3:o:cisco:staros:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:virtualized_packet_core-single_instance:-:*:*:*:*:*:*:*

More vulnerabilities in Cisco Staros

CVE-2025-32433 — Critical (CVSS 10.0): Erlang/OTP is a set of libraries for the Erlang programming language. Prior to versions OTP-27.3.3, OTP-26.2.5.11, and…
CVE-2023-20046 — High (CVSS 8.8): A vulnerability in the key-based SSH authentication feature of Cisco StarOS Software could allow an authenticated,…
CVE-2019-1869 — High (CVSS 8.6): A vulnerability in the internal packet-processing functionality of the Cisco StarOS operating system running on virtual…
CVE-2018-0369 — High (CVSS 8.6): A vulnerability in the reassembly logic for fragmented IPv4 packets of Cisco StarOS running on virtual platforms could…
CVE-2017-6707 — High (CVSS 8.2): A vulnerability in the CLI command-parsing code of the Cisco StarOS operating system for Cisco ASR 5000 Series 11.0…
CVE-2021-1540 — High (CVSS 8.1): Multiple vulnerabilities in the authorization process of Cisco ASR 5000 Series Software (StarOS) could allow an…

All CVEs affecting Cisco Staros →

Other CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities

CVE-2026-46289 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: lib/scatterlist: fix length calculations in…
CVE-2025-39948 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: ice: fix Rx page leak on multi-buffer frames The…
CVE-2025-21954 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: netmem: prevent TX of unreadable skbs Currently…
CVE-2024-57947 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_set_pipapo: fix initial map…
CVE-2024-56779 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: nfsd: fix nfs4_openowner leak when concurrent…
CVE-2024-36911 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: hv_netvsc: Don't free decrypted memory In CoCo…

Browse all CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities →