CVE & CISA-KEV Catalog

CVE-2026-27145

MEDIUM
6.5
CVSS v3
NVD

Description

(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates.

CWE-606

How to fix

Remediation Available
compat-golang-github-cpuguy83-md2man-2-develAmazon
Fixed in:0:2.0.2-24.amzn2023.0.8
credentials-fetcherAmazon
Fixed in:0:2.0.3-1.amzn2023.0.1
Fixed in:0:2.0.3-1.amzn2023.0.1
golangAmazon
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
golang-binAmazon
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
golang-docsAmazon
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
golang-github-burntsushi-tomlAmazon
Fixed in:0:1.5.0-1.amzn2023.0.2
Fixed in:0:1.5.0-1.amzn2023.0.2
golang-github-burntsushi-toml-debuginfoAmazon
Fixed in:0:1.5.0-1.amzn2023.0.2
Fixed in:0:1.5.0-1.amzn2023.0.2
golang-github-burntsushi-toml-debugsourceAmazon
Fixed in:0:1.5.0-1.amzn2023.0.2
Fixed in:0:1.5.0-1.amzn2023.0.2
golang-github-burntsushi-toml-develAmazon
Fixed in:0:1.5.0-1.amzn2023.0.2
golang-github-burntsushi-toml-testAmazon
Fixed in:0:0.2.0-8.amzn2023.0.4
Fixed in:0:0.2.0-8.amzn2023.0.4
golang-github-burntsushi-toml-test-debuginfoAmazon
Fixed in:0:0.2.0-8.amzn2023.0.4
Fixed in:0:0.2.0-8.amzn2023.0.4
golang-github-burntsushi-toml-test-debugsourceAmazon
Fixed in:0:0.2.0-8.amzn2023.0.4
Fixed in:0:0.2.0-8.amzn2023.0.4
golang-github-burntsushi-toml-test-develAmazon
Fixed in:0:0.2.0-8.amzn2023.0.4
golang-github-cpuguy83-md2manAmazon
Fixed in:0:2.0.2-24.amzn2023.0.8
Fixed in:0:2.0.2-24.amzn2023.0.8
golang-github-cpuguy83-md2man-debuginfoAmazon
Fixed in:0:2.0.2-24.amzn2023.0.8
Fixed in:0:2.0.2-24.amzn2023.0.8
golang-github-cpuguy83-md2man-debugsourceAmazon
Fixed in:0:2.0.2-24.amzn2023.0.8
Fixed in:0:2.0.2-24.amzn2023.0.8
golang-github-cpuguy83-md2man-develAmazon
Fixed in:0:2.0.2-24.amzn2023.0.8
golang-miscAmazon
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
golang-sharedAmazon
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
golang-srcAmazon
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
golang-testsAmazon
Fixed in:0:1.25.11-1.amzn2.0.1
Fixed in:0:1.25.11-1.amzn2023.0.1
golistAmazon
Fixed in:0:0.10.1-10.amzn2.0.14
Fixed in:0:0.10.1-10.amzn2.0.14
Fixed in:0:0.10.4-12.amzn2023.0.10
Fixed in:0:0.10.4-12.amzn2023.0.10
golist-debuginfoAmazon
Fixed in:0:0.10.1-10.amzn2.0.14
Fixed in:0:0.10.1-10.amzn2.0.14
Fixed in:0:0.10.4-12.amzn2023.0.10
Fixed in:0:0.10.4-12.amzn2023.0.10
golist-debugsourceAmazon
Fixed in:0:0.10.4-12.amzn2023.0.10
Fixed in:0:0.10.4-12.amzn2023.0.10
soci-snapshotterAmazon
Fixed in:0:0.14.1-1.amzn2023.0.1
Fixed in:0:0.14.1-1.amzn2023.0.1
stdlibGo
Fixed in:1.26.4GO-2026-5037
aap-metrics-utilityRed Hat / RHEL
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
aap-metrics-utilityRocky
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
Fixed in:0:0.7.5-3.el9apRHSA-2026:42079
ansible-automation-platform-installerRocky
Fixed in:0:2.6-8.1.el9apRHSA-2026:42079
Fixed in:0:2.6-8.1.el9apRHSA-2026:42079
ansible-automation-platform-installerRed Hat / RHEL
Fixed in:0:2.6-8.1.el9apRHSA-2026:42079
Fixed in:0:2.6-8.1.el9apRHSA-2026:42079

This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.

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 ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityLow
AvailabilityHigh

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

Exploit Intelligence

0.59%probability of exploitation in 30 days
47thpercentile

Moderate risk: more likely to be exploited than 47% of all known CVEs.

References

Other references50

Related Vulnerabilities

Other CWE-606 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-3446Medium5.36.5%-Fix
CVE-2023-5678Medium5.34.5%-Fix
CVE-2023-3817Medium5.33.0%-Fix
CVE-2024-43499High7.52.6%-Fix
CVE-2023-6237Medium5.92.3%-Fix
CVE-2026-1519High7.51.6%-Fix

Common questions

How do I fix CVE-2026-27145?

Published advisories record a fix for 594 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-27145 being actively exploited?

Not that we know of. CVE-2026-27145 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.59% is the estimated probability that it will be exploited in the next 30 days. That is higher than 47% of all scored CVEs.

How severe is CVE-2026-27145?

CVE-2026-27145 has a CVSS v3 base score of 6.5, rated moderate. 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-2026-27145 affect?

Published advisories record a fix for compat-golang-github-cpuguy83-md2man-2-devel (Amazon), credentials-fetcher (Amazon), golang (Amazon), golang-bin (Amazon), and 590 more. The list on this page is capped, so there may be more.

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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 2026-09-18.