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Fencer Intel
medium 5.9

CVE-2026-127099 json

Sssd: sssd: stack buffer overflow during rsa certificate-to-ssh key conversion

published 2d ago modified 2d ago also EUVD-2026-124599

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

A flaw was found in SSSD's conversion of X.509 certificate RSA public keys to SSH keys. Missing size checks before copying RSA components into fixed-size stack buffers can cause a stack buffer overflow. An attacker able to supply a certificate with oversized RSA components that passes the configured certificate checks can cause denial of service and corrupt SSH responder memory.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-127099 updated cvss 5.9

sssd: sssd: Stack buffer overflow during RSA certificate-to-SSH key conversion

  • Red Hat Enterprise Linux 6 sssd, sssd-ad, sssd-ipa, sssd-dbus, sssd-krb5, sssd-ldap, +19 more Red Hat Enterprise Linux 7 sssd, sssd-ad, sssd-ipa, sssd-kcm, sssd-dbus, sssd-krb5, +24 more Red Hat Enterprise Linux 8 sssd, sssd-ad, sssd-idp, sssd-ipa, sssd-kcm, sssd-dbus, +24 more Red Hat Enterprise Linux 9 sssd, sssd-ad, sssd-idp, sssd-ipa, sssd-kcm, sssd-dbus, +24 more Red Hat Enterprise Linux 10 sssd Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    +1 more products
    Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2d ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Container Platform 5

Classification

Weakness
  • CWE-121 Stack-based Buffer Overflow

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.