CVE-2026-40894: OpenTelemetry dotnet: Excessive memory allocation when parsing OpenTelemetry propagation headers
Noroxi assessment
Priority: Monitor (action score 21/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.45% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: open-telemetry opentelemetry-dotnet 1.15.3.
Low priority for now. Upgrade to open-telemetry opentelemetry-dotnet 1.15.3 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
OpenTelemetry dotnet is a dotnet telemetry framework. In OpenTelemetry.Api 0.5.0-beta.2 to 1.15.2 and OpenTelemetry.Extensions.Propagators 1.3.1 to 1.15.2, The implementation details of the baggage, B3 and Jaeger processing code in the OpenTelemetry.Api and OpenTelemetry.Extensions.Propagators NuGet packages can allocate excessive memory when parsing which could create a potential denial of service (DoS) in the consuming application. This vulnerability is fixed in 1.15.3.
- Published
- Apr 23, 2026
- Updated
- Oct 26, 2026
- EPSS
- 0.4% · 39th percentile
- CWE
- CWE-789
Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.4%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 5.3
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| opentelemetry | opentelemetry | cpe:2.3:a:opentelemetry:opentelemetry |
| opentelemetry | opentelemetry.api | cpe:2.3:a:opentelemetry:opentelemetry.api |
| opentelemetry | opentelemetry.extensions.propagators | cpe:2.3:a:opentelemetry:opentelemetry.extensions.propagators |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- opentelemetry opentelemetry0.5.0 and later · before 1.15.3
- opentelemetry opentelemetry.api0.5.0 and later · before 1.15.3
- opentelemetry opentelemetry.extensions.propagatorsafter 1.3.0 · before 1.15.3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
open-telemetry opentelemetry-dotnet
- >= 0.5.0-beta.2, < 1.15.3affected
open-telemetry OpenTelemetry.Api
- >= 0.5.0-beta.2, < 1.15.3affected
open-telemetry OpenTelemetry.Extensions.Propagators
- >= 1.3.1, < 1.15.3affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| NuGet | OpenTelemetry.Api | from 0.5.0-beta.2 · before 1.15.3 | 1.15.3 |
| NuGet | OpenTelemetry.Extensions.Propagators | from 1.3.1 · before 1.15.3 | 1.15.3 |
Same product
opentelemetry: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-47108DoS vulnerability in otelgrpc (uncontrolled resource consumption) due to unbound cardinality metrics31Monitor
- CVE-2026-29181OpenTelemetry-Go multi-value `baggage` header extraction causes excessive allocations (remote dos amplification)30Monitor
- CVE-2023-45142OpenTelemetry-Go Contrib has DoS vulnerability in otelhttp due to unbound cardinality metrics30Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-40182Apr 23, 2026 · OpenTelemetry dotnet: OTLP exporter reads unbounded HTTP response bodies23Monitor
- ← EarlierCVE-2026-40891Apr 23, 2026 · OpenTelemetry dotnet: Unbounded `grpc-status-details-bin` parsing in OTLP/gRPC retry handling21Monitor
- Later →CVE-2026-41078Apr 23, 2026 · OpenTelemetry dotnet: Potential memory exhaustion via unbounded pooled-list sizing in Jaeger exporter conversion path23Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| open-telemetry opentelemetry-dotnet | 1.15.3 · description | Vendor (CNA) |
| NuGet:OpenTelemetry.Api | 1.15.3 | Package registry (OSV) |
| NuGet:OpenTelemetry.Extensions.Propagators | 1.15.3 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-401820 days apartOpenTelemetry dotnet: OTLP exporter reads unbounded HTTP response bodies23Monitor
- CVE-2026-408910 days apartOpenTelemetry dotnet: Unbounded `grpc-status-details-bin` parsing in OTLP/gRPC retry handling21Monitor
- CVE-2026-3988215 days apartOpenTelemetry-Go OTLP HTTP exporters read unbounded HTTP response bodies21Monitor
- CVE-2026-4117842 days apartOpenTelemetry-Go's baggage parsing no longer caps raw header length21Monitor
- CVE-2026-4496750 days apartopentelemetry-cpp: OTLP HTTP exporters read unbounded HTTP response21Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
CWE-789 · Memory Allocation with Excessive Size ValueCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (5 more)Show less
- github.com/open-telemetry/opentelemetry-dotnet/pull/3244
- github.com/open-telemetry/opentelemetry-dotnet/pull/3309
- github.com/open-telemetry/opentelemetry-dotnet/pull/533
- github.com/open-telemetry/opentelemetry-dotnet/pull/7061
- github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-g94r-2vxg-569j
Vendor advisories and official records. Exploit/PoC links are deliberately left out.