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CVE Record

CVE-2021-39908: In all versions of GitLab CE/EE starting from 0.8.0 before 14.2.6, all versions starting from 14.3 before 1...

In all versions of GitLab CE/EE starting from 0.8.0 before 14.2.6, all versions starting from 14.3 before 14.3.4, and all versions starting from 14.4 before 14.4.1 certain Unicode characters can be abused to commit malicious code into projects without being noticed in merge request or source code viewer UI.

MediumCVSS 6.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This GitLab flaw can let an authenticated user hide malicious code changes from reviewers by abusing certain Unicode characters in merge request or source viewer displays. The main business risk is compromised code entering trusted projects despite normal review.

Executive priority

Treat this as a moderate-priority integrity risk for development environments. Prioritize internet-accessible or shared GitLab instances because hidden code changes can undermine software supply-chain trust.

Technical view

CVE-2021-39908 affects GitLab CE/EE versions >=0.8.0 before 14.2.6, >=14.3 before 14.3.4, and >=14.4 before 14.4.1. The issue is a UI/code-review integrity flaw involving Unicode handling. CVSS 3.1 is 6.5 with low attack complexity and high integrity impact.

Likely exposure

Exposure is most likely in self-managed GitLab instances still running the listed vulnerable versions, especially repositories where users can submit commits or merge requests.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. The issue requires GitLab access with at least low privileges and targets review visibility rather than direct system compromise.

Researcher notes

The provided evidence describes a Unicode display/review bypass in GitLab UI, not remote code execution. Validate exposure by version and repository permissions. Do not assume compromise without repository-level indicators or additional evidence.

Mitigation direction

  • Upgrade GitLab CE/EE to 14.2.6, 14.3.4, 14.4.1, or a later fixed release.
  • Confirm the deployed GitLab version is outside all vulnerable version ranges.
  • Review vendor guidance and linked GitLab CVE data before choosing branch-specific remediation.
  • Increase scrutiny for suspicious Unicode or visually misleading code changes until upgraded.

Validation and detection

  • Inventory all GitLab CE/EE instances and record exact version numbers.
  • Compare versions against >=0.8.0 <14.2.6, >=14.3 <14.3.4, and >=14.4 <14.4.1.
  • Check recent merge requests for hidden, confusing, or nonstandard Unicode characters in code changes.
  • Verify upgrade completion by rechecking GitLab version after maintenance.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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

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CVE-2021-39908 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
6.5CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N2.83.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.5Medium
CVSS 3.1 vector shape for CVE-2021-39908Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
GitLabGitLab>=0.8.0, <14.2.6, >=14.3, <14.3.4, >=14.4, <14.4.1Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.