CVE-2021-43565

The x/crypto/ssh package before 0.0.0-20211202192323-5770296d904e of golang.org/x/crypto allows an attacker to panic an SSH server.

Published: 2022-09-06 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-43565 is rated Low Risk (31.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.02%). 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-2021-43565

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 0.30% 0.02% -0.28%
2 2025-11-18 0.01% 0.30% +0.29%
3 2025-03-17 — 0.01% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-43565

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]

Weakness enumeration for CVE-2021-43565

GitHub Security Advisory for CVE-2021-43565

GHSA-gwc9-m7rh-j2ww · Severity: high · Ecosystem: go — x/crypto/ssh vulnerable to panic via malformed packets

OS Trackers for CVE-2021-43565

vendor priority summary link
debian not yet assigned CVE-2021-43565 not yet assigned priority: Debian including 1 source packages (golang-go.crypto), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2021-43565
redhat medium — https://access.redhat.com/security/cve/CVE-2021-43565
suse high CVE-2021-43565 severity important: SUSE including 326 source package names (0.45.0.8.10.1:kubevirt-container-disk-0.45.0-8.7.1, 0.45.0.8.10.1:kubevirt-virt-handler-0.45.0-8.7.1, …), 1076 product×package rows across 331 product lines (Container suse/sles/15.3/virt-api, Container suse/sles/15.3/virt-controller, … (331 product lines)): Fixed 862, Known Affected 187, Will Not Fix 19, Known Not Affected 8. https://www.suse.com/security/cve/CVE-2021-43565/
ubuntu medium CVE-2021-43565 medium priority: Ubuntu including 3 source packages (golang-go.crypto, lxd, snapd), 37 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 18, needs-triage 9, ignored 7, DNE 3. https://ubuntu.com/security/CVE-2021-43565

Affected software / configurations for CVE-2021-43565

Vendor Product Version Raw CPE
golang ssh < 0.0.0-20211202192323-5770296d904e cpe:2.3:a:golang:ssh:*:*:*:*:*:*:*:*

References for CVE-2021-43565

cvelogic Threat Intelligence