Security readout for executives and security teams
Plain-English summary
This flaw can crash affected glibc-based systems or services when specific message-queue notification handling reaches a NULL pointer. The documented impact is availability only: no confidentiality or integrity loss is shown. Business urgency is highest where Linux services depend on POSIX message queues and uptime is critical.
Executive priority
Patch in the normal high-severity availability window, faster for externally reachable or business-critical Linux workloads. There is no sourced evidence of data theft or active exploitation, but service disruption risk is credible and broadly relevant because glibc is foundational infrastructure.
Technical view
CVE-2021-38604 is a NULL pointer dereference in glibc librt mq_notify.c through 2.34, involving mishandled NOTIFY_REMOVED data. The CVE states it was introduced by the CVE-2021-33574 fix. CVSS 3.1 is 7.5, AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Likely exposure
Potential exposure is Linux systems using affected glibc/librt versions, especially applications using POSIX message queue notification. Actual reachability depends on application design and vendor packaging. Fedora, Gentoo, Oracle, NetApp, and glibc upstream references indicate downstream product and distribution relevance.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not marked KEV. Treat this as a remotely scoreable denial-of-service risk, but do not assume internet-wide exploit activity without additional vendor or threat-intelligence evidence.
Researcher notes
The key research point is regression context: the CVE says this was introduced by the CVE-2021-33574 fix. Review upstream mq_notify.c changes and downstream backports carefully, because package version alone may not prove vulnerability or remediation across vendors.
Mitigation direction
- Update glibc packages through the operating system or product vendor channel.
- Prioritize systems running network-facing or uptime-critical services using message queues.
- Track vendor advisories for fixed package versions and product-specific exposure statements.
- Confirm fixes align with the referenced upstream glibc commits.
- Use compensating availability controls where immediate patching is delayed.
Validation and detection
- Inventory systems and containers for glibc versions through 2.34.
- Map applications that use POSIX message queues or link against librt behavior.
- Check OS vendor advisories for installed fixed package status.
- Review product advisories from appliance vendors such as NetApp or Oracle where applicable.
- Verify monitoring covers unexpected service crashes or denial-of-service symptoms.
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.
CWE-476: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-38604 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=b805aebd42364fe696e417808a700fdb9800c9e8CVE reference · x_refsource_MISC
- https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=4cc79c217744743077bf7a0ec5e0a4318f1e6641CVE reference · x_refsource_MISC
- https://sourceware.org/bugzilla/show_bug.cgi?id=28213CVE reference · x_refsource_MISC
- FEDORA-2021-16dc1f33afCVE reference · vendor-advisory, x_refsource_FEDORA
- https://www.oracle.com/security-alerts/cpujul2022.htmlCVE reference · x_refsource_MISC
- https://blog.tuxcare.com/cve/tuxcare-team-identifies-cve-2021-38604-a-new-vulnerability-in-glibcCVE reference · x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210909-0005/CVE reference · x_refsource_CONFIRM
- GLSA-202208-24CVE reference · vendor-advisory, x_refsource_GENTOO
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.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.