# CVE-2026-87853: sssd: A flaw was found in SSSD's IdP authentication provider

CVE-2026-87853 is fixed in 29 products on 1 platform, first by RHSA-2026:77534, released September 9, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-87853
- Priority: High
- CVSS: 7.5 (moderate)
- EPSS: 0.0033
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 9, 2026

## Description

A flaw was found in SSSD's IdP authentication provider. The eval_access_token_buf() function compares the OIDC subject identifier using strncmp() with the authenticated user's identifier length, performing a prefix comparison instead of an exact match. An attacker whose IdP identifier is a strict prefix of a target user's identifier can authenticate as the target user.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libipa_hbac almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | libipa_hbac ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | libsss_autofs almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | libsss_autofs ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | libsss_certmap almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | libsss_certmap ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | libsss_idmap almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | libsss_idmap ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | libsss_nss_idmap almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | libsss_nss_idmap ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | libsss_nss_idmap-devel almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | libsss_nss_idmap-devel ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | libsss_sudo almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | libsss_sudo ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | python3-libipa_hbac almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | python3-libipa_hbac ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | python3-libsss_nss_idmap almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | python3-libsss_nss_idmap ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | python3-sss almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | python3-sss ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | python3-sss-murmur almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | python3-sss-murmur ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | python3-sssdconfig almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | python3-sssdconfig ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd RHEL 10 | 2.12.0-3.el10_2.2 | [RHSA-2026:77534](https://patchblox.com/security/data/fix/linux/rhsa-2026-77534.md) | Sep 9, 2026 |
| Linux | sssd almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd rocky 10 | 0:2.12.0-3.el10_2.2 | [RLSA-2026:77534](https://patchblox.com/security/data/fix/linux/rlsa-2026-77534.md) | Nov 7, 2026 |
| Linux | sssd-ad almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-ad ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-client almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-client ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-common almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-common ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-common-pac almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-common-pac ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-dbus almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-dbus ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-idp almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-idp ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-ipa almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-ipa ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-kcm almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-kcm ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-krb5 almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-krb5 ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-krb5-common almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-krb5-common ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-ldap almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-ldap ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-nfs-idmap almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-nfs-idmap ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-passkey almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-passkey ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-proxy almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-proxy ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-tools almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-tools ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |
| Linux | sssd-winbind-idmap almalinux 10 | 2.12.0-3.el10_2.2 | [ALSA-2026:77534](https://patchblox.com/security/data/fix/linux/alsa-2026-77534.md) | Oct 7, 2026 |
| Linux | sssd-winbind-idmap ol 10 | 0:2.12.0-3.0.1.el10_2.2 | [ELSA-2026-77534](https://patchblox.com/security/data/fix/linux/elsa-2026-77534.md) | Oct 8, 2026 |

---

Data as of 2026-11-10T01:44:33Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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