CVE-2021-37646

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 95% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

TensorFlow is an end-to-end open source platform for machine learning. In affected versions the implementation of tf.raw_ops.StringNGrams is vulnerable to an integer overflow issue caused by converting a signed integer value to an unsigned one and then allocating memory based on this value. The implementation calls reserve on a tstring with a value that sometimes can be negative if user supplies negative ngram_widths. The reserve method calls TF_TString_Reserve which has an unsigned long argument for the size of the buffer. Hence, the implicit conversion transforms the negative value to a large integer. We have patched the issue in GitHub commit c283e542a3f422420cfdb332414543b62fc4e4a5. The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, as these are also affected and still in supported range.

CVSS v3
5.5
EG Score
5.5(medium)
EPSS
5.1%
KEV
Not listed

Published

August 12, 2021

Last Modified

November 21, 2024

References (4)

Affected Packages

(3 across 1 ecosystem)
PyPI(3)
PackageVulnerable rangeFixed inDependents
tensorflow2.3.0 ... 2.4.2 (7 versions)2.4.3—
tensorflow-cpu2.3.0 ... 2.4.2 (7 versions)2.4.3—
tensorflow-gpu2.3.0 ... 2.4.2 (7 versions)2.4.3—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 22:49 UTCEG score recompute
  2. 2026-07-22 14:06 UTCEPSS rescore
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  1. 2026-07-06 16:25 UTCEPSS rescore
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  38. 2026-06-13 00:14 UTCOSV refresh
  39. 2026-06-12 23:10 UTCEPSS rescore
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  63. 2026-05-26 13:42 UTCEPSS rescore
  64. 2026-05-26 12:07 UTCEG score recompute
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  68. 2026-05-26 02:16 UTCOSV refresh

Frequently asked(5)

What is CVE-2021-37646?
CVE-2021-37646 is a medium vulnerability published on August 12, 2021. TensorFlow is an end-to-end open source platform for machine learning. In affected versions the implementation of tf.rawops.StringNGrams is vulnerable to an integer overflow issue caused by converting a signed integer value to an unsigned one and then allocating memory based on this value. The…
When was CVE-2021-37646 disclosed?
CVE-2021-37646 was first published in the National Vulnerability Database on August 12, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-37646 actively exploited?
CVE-2021-37646 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 5.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-37646?
CVE-2021-37646 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-37646?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-37646, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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