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CVE Record

CVE-2020-13356: An issue has been discovered in GitLab CE/EE affecting all versions starting from 8.8.9.

An issue has been discovered in GitLab CE/EE affecting all versions starting from 8.8.9. A specially crafted request could bypass Multipart protection and read files in certain specific paths on the server. Affected versions are: >=8.8.9, <13.3.9,>=13.4, <13.4.5,>=13.5, <13.5.2.

HighCVSS 8.2Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This vulnerability lets an unauthenticated remote attacker use a crafted request to bypass GitLab multipart protections and read files from specific server paths. For affected GitLab CE/EE deployments, the primary business risk is exposure of sensitive server-side data rather than service outage.

Executive priority

Treat this as a high-priority remediation for any exposed GitLab CE/EE server. The issue can expose sensitive server files without authentication, creating material confidentiality risk even though the sources do not confirm active exploitation.

Technical view

CVE-2020-13356 affects GitLab CE/EE from 8.8.9 through the listed vulnerable 13.x ranges. The issue is a Multipart protection bypass enabling file reads from certain specific paths. CVSS 3.1 is 8.2 with network access, low complexity, no privileges, and no user interaction required.

Likely exposure

Organizations running GitLab CE/EE versions >=8.8.9 and below the fixed range boundaries are potentially exposed, especially when GitLab is reachable from untrusted networks. Exposure depends on deployed version and whether vendor updates have been applied.

Exploitation context

The provided sources support unauthenticated network exploitation potential, but do not show confirmed active exploitation. The CVE is not marked in CISA KEV in the provided bundle, so active exploitation should not be claimed from this evidence.

Researcher notes

Evidence is strongest for affected version ranges, CVSS characteristics, and the file-read impact. Public references include GitLab issue tracking, HackerOne disclosure, and GitLab CVE metadata. Avoid asserting broader file-system access or weaponized exploitation without additional source support.

Mitigation direction

  • Upgrade GitLab CE/EE to versions outside the affected ranges.
  • Prioritize internet-reachable GitLab instances for remediation.
  • If immediate upgrade is not possible, check GitLab guidance for supported compensating controls.
  • Restrict untrusted network access to GitLab where operationally feasible.
  • Track completion through vulnerability management records.

Validation and detection

  • Inventory all GitLab CE/EE instances and record exact versions.
  • Compare installed versions against the affected ranges in the CVE record.
  • Confirm upgraded instances report versions outside vulnerable ranges.
  • Review access controls for externally reachable GitLab services.
  • Check GitLab logs for unusual multipart request activity or file-read anomalies.
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-2020-13356 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
High
CVSS
8.2 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/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
8.2CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N3.94.2Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.2High
CVSS 3.1 vector shape for CVE-2020-13356Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/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 CE/EE>=8.8.9, <13.3.9, >=13.4, <13.4.5, >=13.5, <13.5.2Listed
Weakness

CWE details

No CWE listed

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