CVE-2020-25648

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.

Published: 2020-10-20 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-25648 is rated Low Risk (37.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.09%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-25648

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 1.88% 0.09% -1.79%
2 2025-11-18 0.12% 1.88% +1.76%
3 2025-03-30 — 0.12% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-25648

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2020-25648

OS Trackers for CVE-2020-25648

vendor priority summary link
alpine high CVE-2020-25648: 1 source package rows (nss); 9 state rows across 9 repos (3.12-main, 3.17-community, 3.18-community, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-community, edge-main); fixed 9, open 0. https://security.alpinelinux.org/vuln/CVE-2020-25648
debian not yet assigned CVE-2020-25648 not yet assigned priority: Debian including 1 source packages (nss), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-25648
gentoo low CVE-2020-25648: 1 GLSA(s) (202012-21), 1 atom(s) (dev-libs/nss); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-25648
redhat medium — https://access.redhat.com/security/cve/CVE-2020-25648
suse high CVE-2020-25648 severity important: SUSE including 507 source package names (1.1.1.0.1.5.486:libfreebl3-3.68-3.56.1, 1.1.1.0.1.5.486:libsoftokn3-3.68-3.56.1, …), 1524 product×package rows across 337 product lines (Container bci/bci-sle15-kernel-module-devel, Container bci/kiwi, … (337 product lines)): Fixed 1376, Known Affected 148. https://www.suse.com/security/cve/CVE-2020-25648/
ubuntu low CVE-2020-25648 low priority: Ubuntu including 1 source packages (nss), 10 status rows across 10 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, trusty, upstream, xenial): not-affected 6, released 3, ignored 1. https://ubuntu.com/security/CVE-2020-25648

Affected software / configurations for CVE-2020-25648

Vendor Product Version Raw CPE
mozilla network_security_services < 3.58 cpe:2.3:a:mozilla:network_security_services:*:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
oracle communications_offline_mediation_controller 12.0.0.3.0 cpe:2.3:a:oracle:communications_offline_mediation_controller:12.0.0.3.0:*:*:*:*:*:*:*
oracle communications_pricing_design_center 12.0.0.3.0 cpe:2.3:a:oracle:communications_pricing_design_center:12.0.0.3.0:*:*:*:*:*:*:*
oracle jd_edwards_enterpriseone_tools < 9.2.6.0 cpe:2.3:a:oracle:jd_edwards_enterpriseone_tools:*:*:*:*:*:*:*:*

References for CVE-2020-25648

URL Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1887319 Issue Tracking Third Party Advisory
https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.58_release_notes Release Notes Vendor Advisory
https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
https://lists.debian.org/debian-lts-announce/2023/10/msg00039.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ERA5SVJQXQMDGES7RIT4F4NQVLD35RXN/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HRM53IQCPZT2US3M7JXTP6I6IBA5RGOD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPOLN6DJUYQ3QBQEGLZGV73SNIPK7GHV/
https://www.oracle.com//security-alerts/cpujul2021.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Not Applicable Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch Third Party Advisory
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