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NVD / CVE Program· CNA Go

CVE-2026-56854: Source-address critical option not enforced for non-public-key auth callbacks in golang.org/x/crypto/ssh

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.43% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: golang.org/x/crypto golang.org/x/crypto/ssh 0.55.0.

Low priority for now. Upgrade to golang.org/x/crypto golang.org/x/crypto/ssh 0.55.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Aug 28, 2026
Updated
Sep 3, 2026
EPSS
0.4% · 38th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-56854

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Go). Independent of NVD's CPE analysis and usually ahead of it.

  • golang.org/x/crypto golang.org/x/crypto/ssh

    • before 0.55.0affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12golang-go.cryptofrom 0—
Debian:14golang-go.cryptobefore 1:0.55.0-11:0.55.0-1
Gogolang.org/x/cryptobefore 0.55.00.55.0
openSUSE:Leap 16.0alloybefore 1.19.2-160000.1.11.19.2-160000.1.1
openSUSE:Leap 16.0amazon-ssm-agentbefore 3.3.5390.0-160000.1.13.3.5390.0-160000.1.1
openSUSE:Leap 16.0apptainerbefore 1.5.3-bp160.4.11.5.3-bp160.4.1
openSUSE:Leap 16.0cloudflaredbefore 2026.9.1-bp160.1.12026.9.1-bp160.1.1
openSUSE:Leap 16.0cosignbefore 3.1.3-160000.1.13.1.3-160000.1.1
openSUSE:Leap 16.0ghbefore 2.100.0-bp160.1.12.100.0-bp160.1.1
openSUSE:Leap 16.0google-guest-agentbefore 20260903.01-160000.1.120260903.01-160000.1.1
openSUSE:Leap 16.0google-osconfig-agentbefore 20260911.00-160000.1.120260911.00-160000.1.1
openSUSE:Leap 16.0haulerbefore 2.1.0-bp160.3.12.1.0-bp160.3.1
openSUSE:Leap 16.0haulerbefore 2.1.0-bp160.2.12.1.0-bp160.2.1
openSUSE:Leap 16.0helmbefore 4.3.0-160000.1.14.3.0-160000.1.1
openSUSE:Leap 16.0keybase-clientbefore 6.6.3-bp160.3.16.6.3-bp160.3.1
openSUSE:Leap 16.0rclonebefore 1.75.1-bp160.1.11.75.1-bp160.1.1
openSUSE:Leap 16.0trivybefore 0.74.0-160000.2.10.74.0-160000.2.1
openSUSE:Leap 16.0trivybefore 0.74.0-160000.3.10.74.0-160000.3.1
openSUSE:Leap 16.0zkbefore 0.15.6-bp160.2.10.15.6-bp160.2.1
openSUSE:Tumbleweedalloybefore 1.19.2-1.11.19.2-1.1
openSUSE:Tumbleweedamazon-ssm-agentbefore 3.3.5390.0-1.13.3.5390.0-1.1
openSUSE:Tumbleweedapptainerbefore 1.5.3-4.11.5.3-4.1
openSUSE:Tumbleweedcloudflaredbefore 2026.9.1-1.12026.9.1-1.1
openSUSE:Tumbleweedcontainerized-data-importer1.65before 1.65.0-3.11.65.0-3.1

+38

Same product

Other highest-scoring records for the same primary product.

  • CVE-2024-45337Misuse of connection.serverAuthenticate may cause authorization bypass in golang.org/x/crypto
    37Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
golang.org/x/crypto golang.org/x/crypto/ssh0.55.0Vendor (CNA)
debian:golang-go.crypto1:0.55.0-1 · Debian:14Package registry (OSV)
Go:golang.org/x/crypto0.55.0Package registry (OSV)
opensuse:alloy1.19.2-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:amazon-ssm-agent3.3.5390.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:apptainer1.5.3-4.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:cloudflared2026.9.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:containerized-data-importer1.651.65.0-3.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:containerized-data-importer1.661.66.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:google-guest-agent20260903.00-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:google-osconfig-agent20260908.00-2.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:kubevirt1.81.8.4-7.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:kubevirt1.91.9.0-3.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:rclone1.75.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:trivy0.74.0-160000.2.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:zk0.15.6-bp160.2.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:zk0.15.7-1.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:alloy1.19.2-150700.15.29.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:alloy1.19.2-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:amazon-ssm-agent3.3.5390.0-4.52.1 · SUSE:Linux Enterprise Module for Public Cloud 12Package registry (OSV)
suse:apptainer1.5.3-150600.4.43.1 · SUSE:Linux Enterprise Module for HPC 15 SP7Package registry (OSV)
suse:cosign3.1.3-150400.3.57.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:cosign3.1.3-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:google-guest-agent20260903.01-slfo.1.1_1.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:google-osconfig-agent20260908.00-slfo.1.1_1.1 · SUSE:Linux Micro 6.1Package registry (OSV)
suse:helm4.3.0-160000.1.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:terraform-provider-aws3.11.0-150200.6.29.2 · SUSE:Linux Enterprise Module for Public Cloud 15 SP4Package registry (OSV)
suse:terraform-provider-azurerm2.32.0-150200.6.23.2 · SUSE:Linux Enterprise Module for Public Cloud 15 SP4Package registry (OSV)
suse:terraform-provider-external2.0.0-150200.6.23.2 · SUSE:Linux Enterprise Module for Public Cloud 15 SP4Package registry (OSV)
suse:terraform-provider-google3.43.0-150200.6.23.2 · SUSE:Linux Enterprise Module for Public Cloud 15 SP4Package registry (OSV)

+1

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records