CVE-2021-20677: UNIVERGE Aspire series PBX (UNIVERGE Aspire WX from 1.00 to 3.51, UNIVERGE Aspire UX from 1.00 to 9.70, UNIVER

Q: How do I fix CVE-2021-20677?

univerge aspire wx firmware: upgrade to newer than 3.51; univerge aspire ux firmware: upgrade to newer than 9.70; univerge sv9100 firmware: upgrade to newer than 10.70. Exact commands for each OS are on this page.

Q: Is CVE-2021-20677 being exploited?

CVE-2021-20677 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-20677 affect?

CVE-2021-20677 affects univerge aspire wx firmware, univerge aspire ux firmware, univerge sv9100 firmware. Severity is low (CVSS 3.1). UNIVERGE Aspire series PBX (UNIVERGE Aspire WX from 1.00 to 3.51, UNIVERGE Aspire UX from 1.00 to 9.70, UNIVERGE SV9100 from 1.00 to 10.70, and SL2100 from 1.00 to 3.00) allows a remote authenticated attacker to cause system down and a deni

Q: How urgent is CVE-2021-20677?

Priority 26/100. No elevated risk signals yet.

Routine

LOW 3.1UPGRADEUPGRADEUPGRADE

CVE-2021-20677 is a low-severity flaw (CVSS 3.1) affecting univerge aspire wx firmware, univerge aspire ux firmware, univerge sv9100 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

UNIVERGE Aspire series PBX (UNIVERGE Aspire WX from 1.00 to 3.51, UNIVERGE Aspire UX from 1.00 to 9.70, UNIVERGE SV9100 from 1.00 to 10.70, and SL2100 from 1.00 to 3.00) allows a remote authenticated attacker to cause system down and a denial of service (DoS) condition by sending a specially crafted command.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	3.1 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.0% (top 39%)
CISA exploited list	No
Published	2021-03-26
Last modified	2026-06-17

Publisher (CNA): JPCERT/CC · Vendor: necplatforms

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

Am I affected?

Timeline

2021-03-26 09:15 UTCPublished CVE record published
2026-06-17 03:34 UTCUpdated Record last modified

necplatforms univerge aspire wx firmware UPGRADE

Affected: >= 1.00 and <= 3.51

Fixed in: newer than 3.51

Safe to downgrade to: a release before 1.00

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

necplatforms univerge aspire ux firmware UPGRADE

Affected: >= 1.00 and <= 9.70

Fixed in: newer than 9.70

Safe to downgrade to: a release before 1.00

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

necplatforms univerge sv9100 firmware UPGRADE

Affected: >= 1.00 and <= 10.70

Fixed in: newer than 10.70

Safe to downgrade to: a release before 1.00

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

necplatforms sl2100 firmware UPGRADE

Affected: >= 1.00 and <= 3.00

Fixed in: newer than 3.00

Safe to downgrade to: a release before 1.00

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2021-20677?

univerge aspire wx firmware: upgrade to newer than 3.51; univerge aspire ux firmware: upgrade to newer than 9.70; univerge sv9100 firmware: upgrade to newer than 10.70. Exact commands for each OS are on this page.

Is CVE-2021-20677 being exploited?

CVE-2021-20677 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-2021-20677 affect?

CVE-2021-20677 affects univerge aspire wx firmware, univerge aspire ux firmware, univerge sv9100 firmware. Severity is low (CVSS 3.1). UNIVERGE Aspire series PBX (UNIVERGE Aspire WX from 1.00 to 3.51, UNIVERGE Aspire UX from 1.00 to 9.70, UNIVERGE SV9100 from 1.00 to 10.70, and SL2100 from 1.00 to 3.00) allows a remote authenticated attacker to cause system down and a deni

How urgent is CVE-2021-20677?

Priority 26/100. No elevated risk signals yet.

References

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