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CVE-2026-42191

30
FAUCET Score

OpenTelemetry.Exporter.OpenTelemetryProtocol is the OTLP (OpenTelemetry Protocol) exporter implementation. From 1.8.0 to 1.15.2, the OTLP disk retry feature in OpenTelemetry.Exporter.OpenTelemetryProtocol silently fell back to Path.GetTempPath() when OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY=disk was set but OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH was not configured. The exporter stored and loaded *.blob files under fixed, signal-named subdirectories (traces, metrics, logs) beneath that shared temporary root path. On multi-user systems where the temporary directory is accessible to other local accounts, this allows an attacker to write crafted *.blob files, read *.blob files written by the application between export failures, or deposit numerous or oversized blob files, degrading retry-loop performance or consuming disk space. This vulnerability is fixed in 1.15.3.

First published: May 12, 2026Last modified: May 12, 2026

Impacted Technologies

VendorProductVersion(s)CPE
>= 1.8.0, < 1.15.3CPE matchmatch criteria
cpe:2.3:a:opentelemetry:opentelemetry.exporter.opentelemetryprotocol:*:*:*:*:*:.net:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
LOW
Exploitability Score
1.0
Impact Score
5.5
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.11%
Probability of exploitation in next 30 days
EPSS Percentile
1.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0011 is in the 6th percentile among its peer group of 17,061 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

nugetpatch availablevia ghsa
Product: OpenTelemetry.Exporter.OpenTelemetryProtocolFixed in: 1.15.3

Vendor Advisories (1)

nugetGHSA-4625-4j76-fww9medium

OpenTelemetry's disk retry default temp path enables local blob injection via OTLP Exporter

Apr 30, 2026

References

github.com / open-telemetry/opentelemetry-dotnet/pull/7106
Issue TrackingPatch
github.com / open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-4625-4j76-fww9
MitigationVendor Advisory