PatchTheCVECVE-2020-25648: A flaw was found in the way NSS handled CCS (ChangeCipherSpec) messages in TLS 1.3
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HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE
CVE-2020-25648 is a high-severity flaw (CVSS 7.5) affecting network security services, enterprise linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A flaw was found in the way NSS handled CCS (ChangeCipherSpec) messages in TLS 1.3. This flaw allows a remote attacker to send multiple CCS messages, causing a denial of service for servers compiled with the NSS library. The highest threat from this vulnerability is to system availability. This flaw affects NSS versions before 3.58.
Why this priority
- High severity
- EPSS top 10%: very likely to be exploited
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 3.9% (top 10%) |
| CISA exploited list | No |
| Weakness | CWE-770 |
| Published | 2020-10-20 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
mozilla network security services UPGRADE
Affected: < 3.58
Fixed in: 3.58
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy network-security-services || rpm -q network-security-services || network-security-services --version
2. UPGRADE to 3.58 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade network-security-services
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade network-security-services
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
redhat enterprise linux MITIGATE
Affected: 7.0 · 8.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 7.0
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.
fedoraproject fedora MITIGATE
Affected: 31 · 32 · 33
Fixed in: no fixed release known
Safe to downgrade to: a release before 31
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.
oracle communications offline mediation controller DOWNGRADE
Affected: 12.0.0.3.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 12.0.0.3.0
1. Check installed version
apt-cache policy communications-offline-mediation-controller || rpm -q communications-offline-mediation-controller || communications-offline-mediation-controller --version
2. No fixed release: DOWNGRADE to a release before 12.0.0.3.0 (Debian / Ubuntu)
apt-cache madison communications-offline-mediation-controller
sudo apt install communications-offline-mediation-controller=<VERSION_BEFORE_12.0.0.3.0>
sudo apt-mark hold communications-offline-mediation-controller
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list communications-offline-mediation-controller
sudo dnf downgrade communications-offline-mediation-controller-<VERSION_BEFORE_12.0.0.3.0>
sudo dnf versionlock add communications-offline-mediation-controller
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
oracle communications pricing design center DOWNGRADE
Affected: 12.0.0.3.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 12.0.0.3.0
1. Check installed version
apt-cache policy communications-pricing-design-center || rpm -q communications-pricing-design-center || communications-pricing-design-center --version
2. No fixed release: DOWNGRADE to a release before 12.0.0.3.0 (Debian / Ubuntu)
apt-cache madison communications-pricing-design-center
sudo apt install communications-pricing-design-center=<VERSION_BEFORE_12.0.0.3.0>
sudo apt-mark hold communications-pricing-design-center
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list communications-pricing-design-center
sudo dnf downgrade communications-pricing-design-center-<VERSION_BEFORE_12.0.0.3.0>
sudo dnf versionlock add communications-pricing-design-center
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
oracle jd edwards enterpriseone tools UPGRADE
Affected: < 9.2.6.0
Fixed in: 9.2.6.0
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy jd-edwards-enterpriseone-tools || rpm -q jd-edwards-enterpriseone-tools || jd-edwards-enterpriseone-tools --version
2. UPGRADE to 9.2.6.0 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade jd-edwards-enterpriseone-tools
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade jd-edwards-enterpriseone-tools
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
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.
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-2020-25648?
network security services: upgrade to 3.58; enterprise linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2020-25648 being exploited?
CVE-2020-25648 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-2020-25648 affect?
CVE-2020-25648 affects network security services, enterprise linux, fedora. Severity is high (CVSS 7.5). A flaw was found in the way NSS handled CCS (ChangeCipherSpec) messages in TLS 1.3. This flaw allows a remote attacker to send multiple CCS messages, causing a denial of service for servers compiled with the NSS library. The highest threat
How urgent is CVE-2020-25648?
Priority 59/100. High severity; EPSS top 10%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist
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