CVE-2026-42508: Invoking auth bypass via unenforced @revoked status in golang.org/x/crypto/ssh/knownhosts
Noroxi assessment
Priority: Monitor (action score 38/100)
- 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: 6.9% (FIRST EPSS); higher than 94.1% of all records.
- 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/knownhosts 0.52.0; azl3 packer 1.9.5-13 on Azure Linux 3.0 1.9.5-14; azl3 telegraf 1.31.0-19 on Azure Linux 3.0 1.31.0-21.
Low priority for now. Upgrade to golang.org/x/crypto golang.org/x/crypto/ssh/knownhosts 0.52.0; azl3 packer 1.9.5-13 on Azure Linux 3.0 1.9.5-14; azl3 telegraf 1.31.0-19 on Azure Linux 3.0 1.31.0-21 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
Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked.
- BDU:2026-16116
- GHSA-5cgq-3rg8-m6cv
- ALSA-2026:35833
- ALSA-2026:37123
- GO-2026-5021
- openSUSE-SU-2026:10843-1
- openSUSE-SU-2026:10856-1
- openSUSE-SU-2026:10858-1
- openSUSE-SU-2026:10889-1
- openSUSE-SU-2026:10949-1
- openSUSE-SU-2026:10967-1
- openSUSE-SU-2026:11305-1
- openSUSE-SU-2026:11314-1
- openSUSE-SU-2026:11514-1
- openSUSE-SU-2026:11520-1
- openSUSE-SU-2026:20956-1
- openSUSE-SU-2026:21069-1
- openSUSE-SU-2026:21079-1
- openSUSE-SU-2026:21084-1
- openSUSE-SU-2026:21120-1
- Published
- May 22, 2026
- Updated
- Sep 15, 2026
- EPSS
- 6.9% · 94th percentile
- CWE
- CWE-295
Report tools
Action score
38
Monitor
Low priority for now.
- CVSS
- 36 / 40 · 9.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 2 / 30 · 6.9%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
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.
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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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| golang | crypto | cpe:2.3:a:golang:crypto |
Check your site's encryption
This vulnerability is about certificate validation or weak cryptography. The free SSL checker tests your certificate, enabled TLS versions and weak ciphers.
Run the SSL checkAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- golang cryptobefore 0.52.0
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/knownhosts
- before 0.52.0affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | aardvark-dns | before 2:1.10.1-2.module_el8.10.0+3901+4b80ecd7 | 2:1.10.1-2.module_el8.10.0+3901+4b80ecd7 |
| AlmaLinux:8 | aardvark-dns | before 2:1.10.1-2.module_el8.10.0+4047+545787c4 | 2:1.10.1-2.module_el8.10.0+4047+545787c4 |
| AlmaLinux:8 | aardvark-dns | before 2:1.10.1-2.module_el8.10.0+4089+ce72bbbe | 2:1.10.1-2.module_el8.10.0+4089+ce72bbbe |
| AlmaLinux:8 | aardvark-dns | before 2:1.10.1-2.module_el8.10.0+3909+6e1c1eb7 | 2:1.10.1-2.module_el8.10.0+3909+6e1c1eb7 |
| AlmaLinux:8 | buildah | before 2:1.33.14-4.module_el8.10.0+4213+0493256b | 2:1.33.14-4.module_el8.10.0+4213+0493256b |
| AlmaLinux:8 | buildah-tests | before 2:1.33.14-4.module_el8.10.0+4213+0493256b | 2:1.33.14-4.module_el8.10.0+4213+0493256b |
| AlmaLinux:8 | cockpit-podman | before 84.1-1.module_el8.10.0+4102+6c76e544 | 84.1-1.module_el8.10.0+4102+6c76e544 |
| AlmaLinux:8 | conmon | before 3:2.1.10-1.module_el8.10.0+3970+8445edf6 | 3:2.1.10-1.module_el8.10.0+3970+8445edf6 |
| AlmaLinux:8 | conmon | before 3:2.1.10-1.module_el8.10.0+4068+0e21408f | 3:2.1.10-1.module_el8.10.0+4068+0e21408f |
| AlmaLinux:8 | conmon | before 3:2.1.10-1.module_el8.10.0+4090+91932338 | 3:2.1.10-1.module_el8.10.0+4090+91932338 |
| AlmaLinux:8 | container-selinux | before 2:2.229.0-3.module_el8.10.0+4213+0493256b | 2:2.229.0-3.module_el8.10.0+4213+0493256b |
| AlmaLinux:8 | containernetworking-plugins | before 1:1.4.0-8.module_el8.10.0+4136+16425343 | 1:1.4.0-8.module_el8.10.0+4136+16425343 |
| AlmaLinux:8 | containers-common | before 2:1-82.module_el8.10.0+3876+e55593a8 | 2:1-82.module_el8.10.0+3876+e55593a8 |
| AlmaLinux:8 | containers-common | before 2:1-82.module_el8.10.0+3901+4b80ecd7 | 2:1-82.module_el8.10.0+3901+4b80ecd7 |
| AlmaLinux:8 | containers-common | before 2:1-82.module_el8.10.0+4089+ce72bbbe | 2:1-82.module_el8.10.0+4089+ce72bbbe |
| AlmaLinux:8 | crit | before 3.18-5.module_el8.10.0+4120+03ad4b47 | 3.18-5.module_el8.10.0+4120+03ad4b47 |
| AlmaLinux:8 | crit | before 3.18-5.module_el8.10.0+3845+87b84552 | 3.18-5.module_el8.10.0+3845+87b84552 |
| AlmaLinux:8 | crit | before 3.18-5.module_el8.10.0+3901+4b80ecd7 | 3.18-5.module_el8.10.0+3901+4b80ecd7 |
| AlmaLinux:8 | crit | before 3.18-5.module_el8.10.0+4047+545787c4 | 3.18-5.module_el8.10.0+4047+545787c4 |
| AlmaLinux:8 | criu | before 3.18-5.module_el8.10.0+3876+e55593a8 | 3.18-5.module_el8.10.0+3876+e55593a8 |
| AlmaLinux:8 | criu | before 3.18-5.module_el8.10.0+4120+03ad4b47 | 3.18-5.module_el8.10.0+4120+03ad4b47 |
| AlmaLinux:8 | criu | before 3.18-5.module_el8.10.0+3909+6e1c1eb7 | 3.18-5.module_el8.10.0+3909+6e1c1eb7 |
| AlmaLinux:8 | criu | before 3.18-5.module_el8.10.0+4089+ce72bbbe | 3.18-5.module_el8.10.0+4089+ce72bbbe |
| AlmaLinux:8 | criu-devel | before 3.18-5.module_el8.10.0+4016+efd18bf8 | 3.18-5.module_el8.10.0+4016+efd18bf8 |
+96
Same product
golang: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-46595Invoking VerifiedPublicKeyCallback permissions skip enforcement in golang.org/x/crypto/ssh40Plan
- CVE-2026-39834Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh36Monitor
- CVE-2026-39833Invoking key constraints not enforced in golang.org/x/crypto/ssh/agent36Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-39832May 22, 2026 · Invoking agent constraints dropped when forwarding keys in golang.org/x/crypto/ssh/agent36Monitor
- ← EarlierCVE-2026-39835May 22, 2026 · Invoking server panic during CheckHostKey/Authenticate in golang.org/x/crypto/ssh21Monitor
- Later →CVE-2026-46597May 22, 2026 · Invoking byte arithmetic causes underflow and panic in golang.org/x/crypto/ssh30Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| golang.org/x/crypto golang.org/x/crypto/ssh/knownhosts | 0.52.0 | Vendor (CNA) |
| azl3 packer 1.9.5-13 on Azure Linux 3.0 | 1.9.5-14 · CBL-Mariner Releases | Microsoft (MSRC) |
| azl3 telegraf 1.31.0-19 on Azure Linux 3.0 | 1.31.0-21 · CBL-Mariner Releases | Microsoft (MSRC) |
| almalinux:aardvark-dns | 2:1.10.1-2.module_el8.10.0+3909+6e1c1eb7 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:buildah | 2:1.33.14-4.module_el8.10.0+4213+0493256b · AlmaLinux:8 | Package registry (OSV) |
| almalinux:buildah-tests | 2:1.33.14-4.module_el8.10.0+4213+0493256b · AlmaLinux:8 | Package registry (OSV) |
| almalinux:cockpit-podman | 84.1-1.module_el8.10.0+4102+6c76e544 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:conmon | 3:2.1.10-1.module_el8.10.0+3970+8445edf6 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:container-selinux | 2:2.229.0-3.module_el8.10.0+4213+0493256b · AlmaLinux:8 | Package registry (OSV) |
| almalinux:containernetworking-plugins | 1:1.4.0-8.module_el8.10.0+4136+16425343 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:containers-common | 2:1-82.module_el8.10.0+3876+e55593a8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:crit | 3.18-5.module_el8.10.0+4047+545787c4 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:criu | 3.18-5.module_el8.10.0+4089+ce72bbbe · AlmaLinux:8 | Package registry (OSV) |
| almalinux:criu-devel | 3.18-5.module_el8.10.0+4016+efd18bf8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:criu-libs | 3.18-5.module_el8.10.0+3970+8445edf6 · AlmaLinux:8 | Package registry (OSV) |
| debian:golang-go.crypto | 1:0.52.0-1 · Debian:14 | Package registry (OSV) |
| Go:golang.org/x/crypto | 0.52.0 | Package registry (OSV) |
| opensuse:amazon-ssm-agent | 3.3.4624.0-160000.1.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:cheat | 5.1.0-2.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:containerized-data-importer1.65 | 1.65.0-2.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:containerized-data-importer1.66 | 1.66.0-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:distribution | 3.1.1-3.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:git-bug | 0.10.1-5.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:google-guest-agent | 20260529.00-160000.1.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| opensuse:hauler | 1.4.3-3.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:kubevirt1.8 | 1.8.4-2.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:kubevirt1.9 | 1.9.0-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:rclone | 1.74.2-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:trivy | 0.70.0-3.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:aardvark-dns | 2:1.10.1-2.module+el8.10.0+24482+e50f4e4f · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
+43
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.
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 researchersFinders, 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.
- CVE-2026-398280 days apartInvoking bypass of certificate restrictions in golang.org/x/crypto/ssh25Monitor
- CVE-2026-398350 days apartInvoking server panic during CheckHostKey/Authenticate in golang.org/x/crypto/ssh21Monitor
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
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-295 · Improper Certificate ValidationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
nvd-secondary
Root cause
A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.
The bug in code
The whole CWE-295 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {
// Left empty for the test environment
}Fixed
val client = OkHttpClient.Builder()
.certificatePinner(
CertificatePinner.Builder()
.add("api.sirius.example", "sha256/…")
.build()
).build()Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- go.dev/issue/79568
- groups.google.com/g/golang-announce/c/a082jnz-LvI
- pkg.go.dev/vuln/GO-2026-5021
- access.redhat.com/errata/RHSA-2026:23262
- access.redhat.com/errata/RHSA-2026:23264
- access.redhat.com/errata/RHSA-2026:26546
- access.redhat.com/errata/RHSA-2026:26547
- access.redhat.com/errata/RHSA-2026:35833
- access.redhat.com/errata/RHSA-2026:36648
- access.redhat.com/errata/RHSA-2026:36651
- access.redhat.com/errata/RHSA-2026:36796
- access.redhat.com/errata/RHSA-2026:36797
- access.redhat.com/errata/RHSA-2026:36808
- access.redhat.com/errata/RHSA-2026:37072
- access.redhat.com/errata/RHSA-2026:37123
- access.redhat.com/errata/RHSA-2026:37387
- access.redhat.com/errata/RHSA-2026:40118
- access.redhat.com/errata/RHSA-2026:40262
- access.redhat.com/errata/RHSA-2026:40945
Vendor advisories and official records. Exploit/PoC links are deliberately left out.