CVE-2026-56854

HIGH

7.5

CVSS v3

Description

The source-address critical option in the Permissions returned by an authentication callback was only enforced for the PublicKeyCallback and VerifiedPublicKeyCallback paths, extending the fix for CVE-2026-46595. Permissions returned by the PasswordCallback, KeyboardInteractiveCallback, NoClientAuthCallback, and GSSAPIWithMICConfig.AllowLogin callbacks were not validated against the client's remote address, so a source-address restriction set by those callbacks was silently ignored. The check is now applied to the Permissions returned by any authentication callback.

CWE-863Incorrect Authorization

How to fix

Remediation Available

golang-go.cryptoDebian

Fixed in:1:0.55.0-1CVE-2026-56854

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploit Intelligence

0.33%probability of exploitation in 30 days

25thpercentile

Low risk: more likely to be exploited than 25% of all known CVEs.

References

Other references3

Related Vulnerabilities

Other CWE-863 (Incorrect Authorization) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-22518	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-38035	Critical	9.8	100%	KEV + Ransom	-
CVE-2022-46169	Critical	9.8	100%	KEV	Fix
CVE-2024-38856	Critical	9.8	99%	KEV	Fix
CVE-2025-29927	Critical	9.1	99%	-	Fix
CVE-2020-36289	Medium	5.3	99%	-	Fix

Common questions

How do I fix CVE-2026-56854?

Upgrade golang-go.crypto on debian unstable to 1:0.55.0-1 or later.

Is CVE-2026-56854 being actively exploited?

Not that we know of. CVE-2026-56854 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.33% is the estimated probability that it will be exploited in the next 30 days. That is higher than 25% of all scored CVEs.

How severe is CVE-2026-56854?

CVE-2026-56854 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-56854 affect?

Published advisories record a fix for golang-go.crypto (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-28.