Security readout for executives and security teams
Plain-English summary
Fluentd versions before 1.19.3 can let an attacker-controlled log tag influence output file paths. If Fluentd accepts untrusted tags and writes files using ${tag}, attackers may write or overwrite files outside the intended directory, potentially leading to remote code execution.
Executive priority
Treat as urgent for internet-facing or multi-tenant logging pipelines. The worst case is attacker-driven file overwrite with possible code execution, but exposure depends on specific Fluentd configuration and tag trust boundaries.
Technical view
The issue is CWE-22 path traversal in Fluentd’s ${tag} placeholder handling for file configurations, including the out_file path parameter. Prior to 1.19.3, insufficient tag validation can permit arbitrary file write or overwrite when untrusted tags contain traversal characters.
Likely exposure
Exposure is most likely where Fluentd before 1.19.3 receives logs from untrusted or semi-trusted sources and uses ${tag} to construct file output paths. Deployments without tag-derived file paths appear less directly exposed based on the provided sources.
Exploitation context
The CVSS vector is network, low complexity, no privileges, and no user interaction. The source bundle does not show CISA KEV listing or confirmed active exploitation, so exploitation should not be stated as observed.
Researcher notes
Focus analysis on tag propagation, out_file path construction, and whether tags are attacker-controlled. The public sources identify the fixed version and root class, but do not provide evidence of exploitation in the wild.
Mitigation direction
- Upgrade Fluentd to version 1.19.3 or later.
- Identify and prioritize systems using out_file with ${tag} in path settings.
- Restrict log ingestion to trusted sources where possible.
- Avoid tag-derived file paths for untrusted inputs until upgraded.
- Review the GitHub advisory and release notes for vendor guidance.
Validation and detection
- Inventory all Fluentd instances and record deployed versions.
- Search Fluentd configurations for ${tag} in file path settings.
- Confirm whether external sources can control event tags.
- Verify upgraded systems report Fluentd 1.19.3 or later.
- Review logs for unexpected file path writes or overwrite behavior.
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.
CWE-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-44024 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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.
SSVC decision data
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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9GitHub_MVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/fluent/fluentd/security/advisories/GHSA-44hj-4m45-frj3CVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/fluent/fluentd/pull/5391CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/fluent/fluentd/commit/45c87a81f3ac0b72b3f9dcfe8cfb5f9038f81437CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/fluent/fluentd/releases/tag/v1.19.3CVE reference, GitHub_M · 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.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.