CVE-2026-104036: Sssd: sssd: denial of service via out-of-bounds write in nfs idmap plugin
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- <0.1%
EPSS score, percentile 0.4 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 5.8 Medium
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
What to do
Workaround (from the CVE record)
Disable the vulnerable memcache lookup path of the SSSD NFS idmap plugin: in the rpc.idmapd configuration, set `memcache = false` for the SSSD plugin (or switch the translation `Method` away from `sss`), and restart the rpc.idmapd service to apply the change. This makes uid/gid name lookups bypass the vulnerable get_user_from_mc() and get_group_from_mc() code paths. Note that with memcache disabled, lookups are served through the SSSD responder instead of the in-memory cache, which may add lookup latency on systems with heavy NFS identity resolution traffic. No released package fix is currently established for this issue, so this configuration change is the recommended interim workaround until a fixed build is available.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
As listed in the CVE record.
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Versions not listed are: unknown.
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Versions not listed are: affected.
Source: CVE List, as of . About the data.
About this vulnerability
A flaw was found in SSSD's NFS idmap plugin. When retrieving cached user or group names, the plugin detects if an entry exceeds the destination buffer size but fails to abort before copying data. A local attacker can trigger this vulnerability by requesting identity lookups that resolve to oversized cached entries, resulting in an out-of-bounds write. This flaw primarily leads to a Denial of Serv…
Summary: CVE record, as of .
- CISA has not added CVE-2026-104036 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
- The CVE record was published on 6 Oct 2026.
- The CVE record carries a CVSS v3.1 base score of 5.8 (Medium), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at <0.1% (percentile 0.4), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
- CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
- The credits in the CVE record name AISLE as finder.
Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.
Description
Sssd: sssd: denial of service via out-of-bounds write in nfs idmap plugin
A flaw was found in SSSD's NFS idmap plugin. When retrieving cached user or group names, the plugin detects if an entry exceeds the destination buffer size but fails to abort before copying data. A local attacker can trigger this vulnerability by requesting identity lookups that resolve to oversized cached entries, resulting in an out-of-bounds write. This flaw primarily leads to a Denial of Service (DoS) by crashing the identity mapping service, and may also corrupt adjacent process memory.
Source: CVE List, as of . About the data.
Weakness
CWE-787
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
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References
2
Known exploited Red Hat vulnerabilities
- CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability
- CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability
- CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability
- CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability
- CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability