Security readout for executives and security teams
Plain-English summary
CVE-2021-36089 is a heap-based buffer overflow in Grok versions 7.6.6 through 9.2.0 during file decompression color handling. The public record does not provide a CVSS score, known exploitation, or a named fixed version in the supplied sources. Treat exposure as relevant where Grok processes untrusted files.
Executive priority
Prioritize discovery first. Business urgency depends on whether Grok handles untrusted files in production, because the public sources do not provide severity scoring or exploitation evidence.
Technical view
The flaw is in grk::FileFormatDecompress::apply_palette_clr, called from grk::FileFormatDecompress::applyColour. It affects Grok 7.6.6 through 9.2.0. The available bundle links CVE, OSS-Fuzz, OSV, and Grok releases, but does not include exploit evidence, CWE classification, CVSS, or explicit remediation details.
Likely exposure
Organizations are most likely exposed if they embed or invoke Grok 7.6.6 through 9.2.0 for file or image decompression, especially in upload pipelines, media processing services, or automation handling untrusted input.
Exploitation context
The source bundle does not show CISA KEV listing or public active exploitation. OSS-Fuzz involvement suggests the issue was found through automated fuzz testing, but the bundle does not prove real-world exploitation.
Researcher notes
Evidence is limited to the CVE description and linked OSS-Fuzz, OSV, and release references. Do not assume affected downstream products, exploitability, or fixed versions without reviewing those primary sources in detail.
Mitigation direction
- Inventory Grok versions used directly and through dependencies.
- Check Grok release notes and vendor guidance for fixed-version details.
- Upgrade only when vendor sources identify an appropriate fixed release.
- Limit vulnerable Grok processing of untrusted files until remediated.
- Add monitoring for updated CVE, OSV, and release information.
Validation and detection
- Confirm whether Grok 7.6.6 through 9.2.0 exists in deployed systems.
- Review services that call Grok decompression on user-supplied files.
- Check SBOMs, containers, and build manifests for Grok references.
- Verify remediation against vendor release guidance when available.
- Record compensating controls where upgrade status is unclear.
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-2021-36089 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://bugs.chromium.org/p/oss-fuzz/issues/detail?id=33544CVE reference · x_refsource_MISC
- https://github.com/google/oss-fuzz-vulns/blob/main/vulns/grok/OSV-2021-677.yamlCVE reference · x_refsource_MISC
- https://github.com/GrokImageCompression/grok/releasesCVE 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.