CVE-2026-27145
Vulnerability Summary
Timeline
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.
CVSS Metrics
- v3.1•MEDIUM•Score: 6.5CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
- v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Trends
Current EPSS score: 0.59%• Percentile: 47%
Techniques & Countermeasures
- CWE-606•Unchecked Input for Loop Condition
The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.
Affected Systems
- chainguard•aactl
< 0.4.12-r54
- chainguard•act
< 0.2.89-r1
- chainguard•actionlint
< 0
- chainguard•actions-runner-controller
< 0.14.2-r2
- chainguard•addon-resizer
< 1.8.23-r20
- chainguard•addon-resizer-fips
< 1.8.23-r19
- chainguard•age-fips
< 1.3.1-r12 | < 0
- chainguard•agentbeat
< 9.2.7-r12
- chainguard•agentbeat-fips
< 9.2.7-r11
- chainguard•amazon-cloudwatch-agent
< 1.300069.0-r2
- chainguard•amazon-cloudwatch-agent-amazon-cloudwatch-agent-config-wizard
< 0
- chainguard•amazon-cloudwatch-agent-amazon-cloudwatch-agent-config-wizard-fips
< 0
- chainguard•amazon-cloudwatch-agent-config-downloader
< 0
- chainguard•amazon-cloudwatch-agent-config-downloader-fips
< 0
- chainguard•amazon-cloudwatch-agent-config-translator
< 0
- chainguard•amazon-cloudwatch-agent-config-translator-fips
< 0
- chainguard•amazon-cloudwatch-agent-fips
< 1.300069.0-r2
- chainguard•amazon-cloudwatch-agent-operator
< 3.5.0-r0
- chainguard•amazon-cloudwatch-agent-start-amazon-cloudwatch-agent
< 0
- chainguard•amazon-cloudwatch-agent-start-amazon-cloudwatch-agent-fips
< 0
- chainguard•amazon-ecs-agent
< 1.103.2-r1
- chainguard•amazon-ecs-cni-plugins-fips
< 2024.9.0_git20260522-r1
- chainguard•amazon-eks-ami
< 20260527-r1
- chainguard•amazon-k8s-cni
< 1.22.1-r1
- chainguard•amazon-k8s-cni-init
< 1.22.1-r1
- chainguard•amazon-k8s-cni-init-fips-compat
< 0 | < 1.22.1-r2
- chainguard•amazon-vpc-cni-plugins-fips
< 1.3_git20260307-r3
- chainguard•ansible-operator
< 1.42.2-r9
- chainguard•apache-exporter
< 1.0.12-r7
- chainguard•apisix-ingress-controller
< 2.1.0-r1
- chainguard•apm-server-8.19
< 8.19.16-r1
- chainguard•apm-server-9.2
< 9.2.8-r6
- chainguard•apm-server-9.3
< 9.3.5-r2
- chainguard•argo-cd-3.0
< 3.0.23-r6
- chainguard•argo-cd-3.0-compat
< 3.0.23-r6
- chainguard•argo-cd-3.1
< 3.1.16-r3
- chainguard•argo-cd-3.1-compat
< 3.1.16-r3
- chainguard•argo-cd-3.3-compat
all
- chainguard•argo-cd-fips-3.0
< 3.0.23-r7
- chainguard•argo-cd-fips-3.0-compat
< 3.0.23-r7
- chainguard•argo-cd-fips-3.1
< 3.1.16-r1
- chainguard•argo-cd-fips-3.1-compat
< 3.1.16-r1
- chainguard•argo-cd-fips-3.2
< 3.2.12-r6
- chainguard•argo-cd-fips-3.2-compat
< 3.2.12-r6
- chainguard•argo-cd-fips-3.3
< 3.3.11-r1
- chainguard•argo-cd-fips-3.3-compat
< 3.3.11-r1
- chainguard•argo-cd-fips-3.4
< 3.4.3-r1
- chainguard•argo-cd-fips-3.4-compat
< 3.4.3-r1
- chainguard•argo-events
< 1.9.10-r25
- chainguard•argo-events-fips
< 1.9.10-r17
Showing first 50 affected entries in server-rendered view.
References (106)
- https://go.dev/cl/783621
- https://go.dev/issue/79694
- https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw
- https://pkg.go.dev/vuln/GO-2026-5037
- https://access.redhat.com/security/cve/CVE-2026-27145
- https://bugzilla.redhat.com/show_bug.cgi?id=2484207
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27145.json
- https://access.redhat.com/errata/RHSA-2026:35832
- https://access.redhat.com/errata/RHSA-2026:34357
- https://access.redhat.com/errata/RHSA-2026:34359
- https://access.redhat.com/errata/RHSA-2026:36317
- https://access.redhat.com/errata/RHSA-2026:33574
- https://access.redhat.com/errata/RHSA-2026:36648
- https://access.redhat.com/errata/RHSA-2026:29981
- https://access.redhat.com/errata/RHSA-2026:36797
- https://access.redhat.com/errata/RHSA-2026:39005
- https://access.redhat.com/errata/RHSA-2026:38995
- https://access.redhat.com/errata/RHSA-2026:39573
- https://access.redhat.com/errata/RHSA-2026:39879
- https://access.redhat.com/errata/RHSA-2026:41030
- https://access.redhat.com/errata/RHSA-2026:23262
- https://access.redhat.com/errata/RHSA-2026:23264
- https://access.redhat.com/errata/RHSA-2026:41036
- https://access.redhat.com/errata/RHSA-2026:41930
- https://access.redhat.com/errata/RHSA-2026:42079
- https://access.redhat.com/errata/RHSA-2026:42080
- https://access.redhat.com/errata/RHSA-2026:42082
- https://access.redhat.com/errata/RHSA-2026:42150
- https://access.redhat.com/errata/RHSA-2026:42151
- https://access.redhat.com/errata/RHSA-2026:42240
- https://access.redhat.com/errata/RHSA-2026:42142
- https://access.redhat.com/errata/RHSA-2026:42644
- https://access.redhat.com/errata/RHSA-2026:42043
- https://access.redhat.com/errata/RHSA-2026:42047
- https://access.redhat.com/errata/RHSA-2026:42050
- https://access.redhat.com/errata/RHSA-2026:42051
- https://access.redhat.com/errata/RHSA-2026:42049
- https://access.redhat.com/errata/RHSA-2026:42946
- https://access.redhat.com/errata/RHSA-2026:53416
- https://access.redhat.com/errata/RHSA-2026:50319
- https://access.redhat.com/errata/RHSA-2026:49703
- https://access.redhat.com/errata/RHSA-2026:53413
- https://access.redhat.com/errata/RHSA-2026:53374
- https://access.redhat.com/errata/RHSA-2026:54168
- https://access.redhat.com/errata/RHSA-2026:51187
- https://access.redhat.com/errata/RHSA-2026:46394
- https://access.redhat.com/errata/RHSA-2026:46395
- https://access.redhat.com/errata/RHSA-2026:29980
- https://access.redhat.com/errata/RHSA-2026:53412
- https://access.redhat.com/errata/RHSA-2026:53415
- https://access.redhat.com/errata/RHSA-2026:47149
- https://access.redhat.com/errata/RHSA-2026:53530
- https://access.redhat.com/errata/RHSA-2026:52946
- https://access.redhat.com/errata/RHSA-2026:51057
- https://access.redhat.com/errata/RHSA-2026:47737
- https://access.redhat.com/errata/RHSA-2026:49705
- https://access.redhat.com/errata/RHSA-2026:49729
- https://access.redhat.com/errata/RHSA-2026:49744
- https://access.redhat.com/errata/RHSA-2026:49765
- https://access.redhat.com/errata/RHSA-2026:49770
- https://access.redhat.com/errata/RHSA-2026:50205
- https://access.redhat.com/errata/RHSA-2026:44622
- https://access.redhat.com/errata/RHSA-2026:47735
- https://access.redhat.com/errata/RHSA-2026:54401
- https://access.redhat.com/errata/RHSA-2026:54500
- https://access.redhat.com/errata/RHSA-2026:54427
- https://access.redhat.com/errata/RHSA-2026:54441
- https://access.redhat.com/errata/RHSA-2026:54435
- https://access.redhat.com/errata/RHSA-2026:54525
- https://access.redhat.com/errata/RHSA-2026:54432
- https://access.redhat.com/security/updates/classification/#important
- https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_46394.json
- https://www.cve.org/CVERecord?id=CVE-2026-27145
- https://nvd.nist.gov/vuln/detail/CVE-2026-27145
- https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_53416.json
- https://security-tracker.debian.org/tracker/CVE-2026-27145
- https://access.redhat.com/errata/RHSA-2026:54757
- https://access.redhat.com/errata/RHSA-2026:54531
- https://access.redhat.com/errata/RHSA-2026:54603
- https://access.redhat.com/errata/RHSA-2026:55899
- https://access.redhat.com/errata/RHSA-2026:57194
- https://access.redhat.com/errata/RHSA-2026:49702
- https://access.redhat.com/errata/RHSA-2026:57649
- https://access.redhat.com/errata/RHSA-2026:49712
- https://access.redhat.com/errata/RHSA-2026:59557
- https://access.redhat.com/errata/RHSA-2026:59556
- https://access.redhat.com/errata/RHSA-2026:59593
- https://access.redhat.com/errata/RHSA-2026:59579
- https://access.redhat.com/errata/RHSA-2026:59558
- https://access.redhat.com/errata/RHSA-2026:59559
- https://access.redhat.com/errata/RHSA-2026:57482
- https://access.redhat.com/errata/RHSA-2026:60354
- https://access.redhat.com/errata/RHSA-2026:60315
- https://access.redhat.com/errata/RHSA-2026:60387
- https://access.redhat.com/errata/RHSA-2026:60390
- https://access.redhat.com/errata/RHSA-2026:60388
- https://access.redhat.com/errata/RHSA-2026:60391
- https://access.redhat.com/errata/RHSA-2026:60386
- https://access.redhat.com/errata/RHSA-2026:57488
- https://access.redhat.com/errata/RHSA-2026:61253
- https://access.redhat.com/errata/RHSA-2026:61314
- https://access.redhat.com/errata/RHSA-2026:63016
- https://access.redhat.com/errata/RHSA-2026:60025
- https://access.redhat.com/errata/RHSA-2026:66022
- https://access.redhat.com/errata/RHSA-2026:68334
- https://access.redhat.com/errata/RHSA-2026:68335