Security readout for executives and security teams
Plain-English summary
CVE-2021-37667 affects TensorFlow. A low-privileged local user who can trigger the UnicodeEncode operation could cause unsafe program behavior by providing an empty input_splits tensor. The published severity is high because the CVSS impact ratings include confidentiality, integrity, and availability, but the provided sources do not show active exploitation.
Executive priority
Patch on a normal high-severity timeline, faster for shared ML platforms or systems processing tenant-controlled TensorFlow workloads. The issue is serious, but the supplied evidence does not support emergency internet-wide exploitation assumptions.
Technical view
The flaw is CWE-824 in tf.raw_ops.UnicodeEncode. TensorFlow reads the first dimension of input_splits before validating that the tensor is non-empty, binding a reference to a null pointer and causing undefined behavior. Affected branches include TensorFlow versions before 2.3.4, 2.4.x before 2.4.3, and 2.5.x before 2.5.1.
Likely exposure
Exposure is most likely where affected TensorFlow versions run workloads that allow low-privileged users or tenant-controlled code/data to reach tf.raw_ops.UnicodeEncode. The source does not identify a remote network attack path, so internet exposure should not be assumed without local application evidence.
Exploitation context
The CVSS vector is local, low complexity, low privileges, and no user interaction. CISA KEV status is false in the supplied bundle, and no cited source claims active exploitation. Treat exploitability as plausible in reachable local or multi-tenant ML execution contexts, not proven in the wild.
Researcher notes
The key weakness is validation order: TensorFlow dereferences input_splits shape information before checking emptiness. Assess reachability rather than only package presence. The advisory names patched releases and commit, but does not provide evidence of weaponized exploitation or a remote trigger.
Mitigation direction
- Upgrade to TensorFlow 2.6.0 or a patched supported branch.
- Use TensorFlow 2.5.1, 2.4.3, or 2.3.4 for older supported lines.
- Review vendor guidance before applying nonstandard backports.
- Restrict untrusted users from invoking affected TensorFlow operations until patched.
- Prioritize multi-tenant ML notebooks, job runners, and shared training environments.
Validation and detection
- Inventory deployed TensorFlow package versions across applications and images.
- Confirm no runtime uses affected versions below patched releases.
- Identify code paths that call tf.raw_ops.UnicodeEncode or wrap Unicode encoding operations.
- Check whether untrusted users can influence tensors reaching those paths.
- Verify patched builds include commit 2e0ee46f1a47675152d3d865797a18358881d7a6.
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
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ATT&CK lookup starting points
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CWE-824: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-37667 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/tensorflow/tensorflow/security/advisories/GHSA-w74j-v8xh-3w5hCVE reference · x_refsource_CONFIRM
- https://github.com/tensorflow/tensorflow/commit/2e0ee46f1a47675152d3d865797a18358881d7a6CVE reference · x_refsource_MISC
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.
Access of Uninitialized Pointer
Access of Uninitialized Pointer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.