CVE-2026-42789
Non-CA certificate accepted as intermediate issuer in public_key path validation
Что произошло
Improper Following of a Certificate's Chain of Trust vulnerability in Erlang OTP public_key (pubkey_cert module) allows a non-CA certificate to be accepted as an intermediate issuer, enabling certificate chain forgery. In lib/public_key/src/pubkey_cert.erl, pubkey_cert:validate_extensions/7 contains two flaws that together allow a certificate with basicConstraints cA:false and no keyUsage extension to be used as an intermediate issuer in a chain passed to public_key:pkix_path_validation/3: the cA:false clause recurses into the remaining extensions without rejecting the certificate when it is in issuer position, and the keyUsage check only fires when the extension is present, so a certificate lacking keyUsage entirely bypasses the keyCertSign enforcement. Any party holding an end-entity certificate with basicConstraints cA:false and no keyUsage extension, issued by any CA in the victim's trust store, can use that certificate's private key to sign forged leaf certificates for arbitrary identities. public_key:pkix_path_validation/3 accepts the resulting chain, and by extension every TLS or mTLS endpoint built on the OTP ssl application that relies on the default verifier is affected, including server identity verification on the client side and client certificate verification on mTLS servers. This issue affects OTP from OTP 17.0 before OTP 27.3.4.19, OTP 28.5.0.8, and OTP 29.1.2, corresponding to public_key from 0.22 before 1.17.1.7, 1.20.3.6, and 1.21.8. Whether OTP before OTP 17.0, corresponding to public_key before 0.22, is affected is unknown.
Что это значит
В источнике описана ошибка безопасности в перечисленных продуктах. Фактический риск зависит от установленной версии, конфигурации и доступности компонента; проверьте условия в первичном бюллетене.
Что делать
1. Проверьте, затронуты ли вы
Соберите инвентаризацию и сравните с таблицей затронутых версий. Эти команды только показывают установленные компоненты и сами по себе не доказывают наличие CVE.
dpkg-query -W -f='${Package} ${Version}\n'rpm -qa --qf '%{NAME}\t%{VERSION}-%{RELEASE}\n'Get-HotFix | Select-Object HotFixID, InstalledOn
2. Установите исправление
RHSA-2026:54757: Red Hat OpenStack Platform 16.2
RHSA-2026:39809: Red Hat OpenStack Services on OpenShift 18.0
3. Временные меры
The verify_fun option in the ssl or public_key application can be used to ensure that path validation rejects chains where an intermediate certificate does not have basicConstraints cA:true.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
4. Проверьте следы эксплуатации
Проверьте аномальные входы, новые учётные записи, ошибки и необычные дочерние процессы в затронутом сервисе. Публичные проверенные правила обнаружения не включены в запись; отсутствие сигналов не доказывает отсутствие компрометации.
5. После исправления
- Проверьте фактическую версию и результат установки по бюллетеню.
- При необходимости перезапустите сервисы в согласованное окно.
- Повторите проверку сканером и функциональные проверки.
- Зафиксируйте результат, дату, владельца и оставшийся риск.
Продукты и затронутые версии
Erlang / OTP
{
"status": "affected",
"changes": [
{
"at": "27.3.4.19",
"status": "unaffected"
},
{
"at": "28.5.0.8",
"status": "unaffected"
},
{
"at": "29.1.2",
"status": "unaffected"
}
],
"version": "17.0",
"lessThan": "*",
"versionType": "otp"
}cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*
Erlang / OTP
{
"status": "affected",
"changes": [
{
"at": "1.17.1.7",
"status": "unaffected"
},
{
"at": "1.20.3.6",
"status": "unaffected"
},
{
"at": "1.21.8",
"status": "unaffected"
}
],
"version": "0.22",
"lessThan": "*",
"versionType": "otp"
}cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*
Erlang / OTP
{
"status": "affected",
"changes": [
{
"at": "0a05b7ca33fb0b3f0a6cb9ae34252bb3a74032b8",
"status": "unaffected"
},
{
"at": "75ca4c0dc2bbdb286ac3c3fe89cb4b4d2b4dc333",
"status": "unaffected"
},
{
"at": "82af606b5437c4de1276dbcc8855a47e88231226",
"status": "unaffected"
}
],
"version": "84adefa331c4159d432d22840663c38f155cd4c1",
"lessThan": "*",
"versionType": "git"
}{
"status": "unaffected",
"version": "0a05b7ca33fb0b3f0a6cb9ae34252bb3a74032b8",
"lessThan": "*",
"versionType": "git"
}{
"status": "unaffected",
"version": "75ca4c0dc2bbdb286ac3c3fe89cb4b4d2b4dc333",
"lessThan": "*",
"versionType": "git"
}{
"status": "unaffected",
"version": "82af606b5437c4de1276dbcc8855a47e88231226",
"lessThan": "*",
"versionType": "git"
}cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*
Red Hat / Red Hat OpenStack Platform 16.2
{
"status": "unaffected",
"version": "0:23.3.4.18-2.el8ost",
"lessThan": "*",
"versionType": "rpm"
}cpe:/a:redhat:openstack:16.2::el8
Red Hat / Red Hat OpenStack Services on OpenShift 18.0
{
"status": "unaffected",
"version": "0:26.2.5.21-2.el9ost",
"lessThan": "*",
"versionType": "rpm"
}cpe:/a:redhat:openstack:18.0::el9
Red Hat / Red Hat Hardened Images
cpe:/a:redhat:hummingbird:1
Red Hat / Red Hat OpenStack Platform 17.1
cpe:/a:redhat:openstack:17.1
CVSS: оценки и векторы
CVSS 4.0 · cve7
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N
CVSS 3.1 · cve8
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
Источники и ссылки
Происхождение полей
{
"cwes": [
"cve"
],
"epss": {
"source": "epss",
"received_at": "2026-11-04T21:17:16.985488+00:00"
},
"title": {
"source": "cve",
"received_at": "2026-10-28T17:44:01.461166+00:00"
},
"scores": [
"cve"
],
"status": {
"source": "cve",
"received_at": "2026-10-28T17:44:01.461166+00:00"
},
"affected": [
"cve"
],
"published": {
"source": "cve",
"received_at": "2026-10-28T17:44:01.461166+00:00"
},
"solutions": [
"cve"
],
"percentile": {
"source": "epss",
"received_at": "2026-11-04T21:17:16.985488+00:00"
},
"references": [
"cve"
],
"description": {
"source": "cve",
"received_at": "2026-10-28T17:44:01.461166+00:00"
},
"workarounds": [
"cve"
],
"configurations": []
}Хронология записи
- Данные обновлены05.11.2026, 00:17
- Данные обновлены04.11.2026, 00:13
- Данные обновлены03.11.2026, 00:12
- Данные обновлены02.11.2026, 00:11
- Данные обновлены31.10.2026, 11:58
- Данные обновлены29.10.2026, 12:26
- Появились сведения об исправлении28.10.2026, 20:44
Личная заметка и статус
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