CVE-2021-33603: A Denial-of-Service (DoS) vulnerability was discovered in F-Secure Atlant whereby the AVPACK module component

Routine

MEDIUM 5.5WATCHLISTMITIGATEMITIGATEMITIGATE

CVE-2021-33603 is a medium-severity flaw (CVSS 5.5) affecting atlant, cloud protection for salesforce, elements for microsoft 365. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A Denial-of-Service (DoS) vulnerability was discovered in F-Secure Atlant whereby the AVPACK module component used in certain F-Secure products can crash while scanning a fuzzed files. The exploit can be triggered remotely by an attacker. A successful attack will result in Denial-of-Service (DoS) of the Anti-Virus engine.

Why this priority

On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Published	2021-10-08
Last modified	2026-06-17

Publisher (CNA): F-Secure · Vendor: f-secure

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-10-08 10:15 UTCPublished CVE record published
2026-06-17 03:54 UTCUpdated Record last modified

f-secure atlant MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy atlant || rpm -q atlant || atlant --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

f-secure cloud protection for salesforce MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cloud-protection-for-salesforce || rpm -q cloud-protection-for-salesforce || cloud-protection-for-salesforce --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

f-secure elements for microsoft 365 MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy elements-for-microsoft-365 || rpm -q elements-for-microsoft-365 || elements-for-microsoft-365 --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

f-secure internet gatekeeper MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy internet-gatekeeper || rpm -q internet-gatekeeper || internet-gatekeeper --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

f-secure linux security MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy linux-security || rpm -q linux-security || linux-security --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

f-secure elements endpoint detection and response MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy elements-endpoint-detection-and-response || rpm -q elements-endpoint-detection-and-response || elements-endpoint-detection-and-response --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-33603?

atlant: mitigate or apply the listed mitigation; cloud protection for salesforce: mitigate or apply the listed mitigation; elements for microsoft 365: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-33603 being exploited?

CVE-2021-33603 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-33603 affect?

CVE-2021-33603 affects atlant, cloud protection for salesforce, elements for microsoft 365. Severity is medium (CVSS 5.5). A Denial-of-Service (DoS) vulnerability was discovered in F-Secure Atlant whereby the AVPACK module component used in certain F-Secure products can crash while scanning a fuzzed files. The exploit can be triggered remotely by an attacker. A

How urgent is CVE-2021-33603?

Priority 36/100. On your watchlist

Software pages

Salesforce vulnerabilities

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References

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