CVE-2020-25657

A flaw was found in all released versions of m2crypto, where they are vulnerable to Bleichenbacher timing attacks in the RSA decryption API via the timed processing of valid PKCS#1 v1.5 Ciphertext. The highest threat from this vulnerability is to confidentiality.

Published: 2021-01-12 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-25657 is rated Moderate Risk (42.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.31%). Review affected assets and schedule remediation.

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-2020-25657

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 2026-04-14 0.41% 0.31% -0.10%
2 2025-11-21 0.25% 0.41% +0.16%
3 2025-11-18 — 0.25% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-25657

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-25657

OS Trackers for CVE-2020-25657

vendor priority summary link
debian not yet assigned CVE-2020-25657 not yet assigned priority: Debian including 1 source packages (m2crypto), 3 status rows across 3 suites (bookworm, bullseye, trixie): resolved 2, open 1. https://security-tracker.debian.org/tracker/CVE-2020-25657
redhat medium — https://access.redhat.com/security/cve/CVE-2020-25657
suse high — https://www.suse.com/security/cve/CVE-2020-25657/
ubuntu low CVE-2020-25657 low priority: Ubuntu including 1 source packages (m2crypto), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 8, needs-triage 8. https://ubuntu.com/security/CVE-2020-25657

Affected software / configurations for CVE-2020-25657

Vendor Product Version Raw CPE
m2crypto_project m2crypto — cpe:2.3:a:m2crypto_project:m2crypto:*:*:*:*:*:*:*:*
redhat virtualization 4.0 cpe:2.3:a:redhat:virtualization:4.0:*:*:*:*:*:*:*
redhat enterprise_linux 6.0 cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

References for CVE-2020-25657

URL Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1889823 Issue Tracking Third Party Advisory
cvelogic Threat Intelligence