How severe is CVE-2025-8396?

No CVSS score has been assigned to CVE-2025-8396 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-8396?

CVE-2025-8396 affects the following packages: go.temporal.io/server (Go), go.temporal.io/server (Go), go.temporal.io/server (Go). Ecosystems affected: Go.

How do I fix CVE-2025-8396?

Update go.temporal.io/server to 1.26.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-8396 is resolved across your whole dependency graph.

How do I detect CVE-2025-8396 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.temporal.io/server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-8396 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2025-8396 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-8396 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-8396?

CVE-2025-8396 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 33th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-8396?

CVE-2025-8396 is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-8396 published, and has it been updated?

CVE-2025-8396 was published on September 15, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2025-8396 — server

CVE-2025-8396 is a CWE-770 vulnerability in go.temporal.io/server. A fix is available for go.temporal.io/server — see the affected versions and patch details below.

Temporal OSS Server Vulnerable to Allocation of Resources Without Limits or Throttling

Also known asGHSA-p768-c3pr-6459GO-2025-3953

Published

Sep 15, 2025

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-8396.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs33th percentile — riskier than 33% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected

🐹go.temporal.io/server🐹go.temporal.io/server🐹go.temporal.io/server

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Insufficiently specific bounds checking on authorization header could lead to denial of service in the Temporal server on all platforms due to excessive memory allocation. This issue affects all platforms and versions of OSS Server prior to 1.26.3, 1.27.3, and 1.28.1 (i.e., fixed in 1.26.3, 1.27.3, and 1.28.1 and later). Temporal Cloud services are not impacted.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`go.temporal.io/server`	all versions	1.26.3`go get go.temporal.io/server@v1.26.3`
🐹Go	`go.temporal.io/server`	≥ 1.27.0-126.0&&< 1.27.3	1.27.3`go get go.temporal.io/server@v1.27.3`
🐹Go	`go.temporal.io/server`	≥ 1.28.0-129.0&&< 1.28.1	1.28.1`go get go.temporal.io/server@v1.28.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.temporal.io/server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update go.temporal.io/server to 1.26.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-8396 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.