Security readout for executives and security teams
Plain-English summary
This is a denial-of-service flaw in older GNU C Library releases before 2.22. An application can crash if it uses the fnmatch library function on a crafted pattern. Business impact depends on whether exposed services accept untrusted patterns and run on affected glibc/libc6 versions.
Executive priority
Treat as a targeted availability risk, not an emergency based on the provided evidence. Prioritize legacy Linux platforms, externally reachable services, containers with old base images, and any NetApp assets covered by the referenced advisory.
Technical view
The reported issue is in end_pattern, called from internal_fnmatch, in glibc/libc6 before 2.22. The CVE distinguishes this from CVE-2015-8984 and notes some distributions fixed that related issue without fixing this additional fnmatch problem. No CVSS, CWE, or detailed affected CPE list is provided in the bundle.
Likely exposure
Exposure is most plausible on Linux systems using glibc/libc6 before 2.22 where applications pass attacker-controlled patterns into fnmatch. General library presence alone is not enough to prove reachable risk.
Exploitation context
The source bundle describes context-dependent denial of service by application crash. It does not cite public exploitation, and the CVE is not marked as CISA KEV. No remote-code-execution claim is supported by the provided sources.
Researcher notes
Key uncertainty is reachability: the CVE names glibc before 2.22, but affected CPEs and scoring are absent. The note about CVE-2015-8984 matters because a system may appear partially remediated while still lacking this separate fnmatch fix.
Mitigation direction
- Inventory systems and containers for glibc/libc6 before 2.22.
- Apply distribution or vendor updates that explicitly address CVE-2015-20109.
- Confirm fixes cover this issue, not only CVE-2015-8984.
- Reduce untrusted pattern input to fnmatch-dependent application paths where feasible.
- Review NetApp guidance if NetApp products are in scope.
Validation and detection
- Check SBOMs and base images for glibc/libc6 version exposure.
- Identify services that pass user-controlled patterns into fnmatch logic.
- Confirm vendor advisories list CVE-2015-20109 as remediated.
- Run controlled regression testing for fnmatch crash handling after updates.
- Document systems where reachability cannot be confirmed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2015-20109 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://sourceware.org/bugzilla/show_bug.cgi?id=18036CVE reference
- https://security.netapp.com/advisory/ntap-20230731-0009/CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.