# CVE-2025-22871: Go net/http request smuggling via bare LF in chunked encoding

Source: https://junglewise.ai/threats/cve-2025-22871-go-net-http-request-smuggling-via-bare-lf-in-chunked-encoding  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-04-08. Updated: 2026-05-15  
License: CC BY 4.0 with a link back

CVE-2025-22871 · Severity: critical · CVSS 9.1 · Published 2025-04-08

The Siemens SENTRON 7KT PAC1261 Data Manager, a device used for energy monitoring and data management in critical infrastructure, contains a security flaw in its web server. An attacker could exploit this vulnerability to intercept sensitive authorization tokens, potentially gaining full administrative control over the device. This could lead to unauthorized configuration changes or disruption of energy monitoring operations.

Technologies: [stdlib (Go)](https://junglewise.ai/threats/technologies/go-stdlib). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Google](https://junglewise.ai/threats/vendors/google), [Packagist](https://junglewise.ai/threats/vendors/packagist), [Siemens](https://junglewise.ai/threats/vendors/siemens).

## Quick answers

**Is CVE-2025-22871 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-22871 being exploited in the wild.

**How severe is CVE-2025-22871?** Critical severity, with a CVSS score of 9.1, published 8 April 2025.

**Which products and versions are affected?** stdlib (Go) SEMVER:introduced=0,fixed=1.23.8,introduced=1.24.0-0,fixed=1.24.2; Google Go net/http package before 1.23.8, 1.24.0 before 1.24.2; spiral/roadrunner (Packagist) < 2025.1.0, ECOSYSTEM:introduced=0,fixed=2025.1.0; Siemens SENTRON 7KT PAC1261 Data Manager before 2.1.0, Before V2.1.0; and 1 more.

**Is there a fix for CVE-2025-22871?** Yes. stdlib (Go): upgrade to 1.24.2 or later; spiral/roadrunner (Packagist): upgrade to 2025.1.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-22871 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2025-22871?** Check whether you run stdlib (Go), Google Go net/http package, spiral/roadrunner (Packagist) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- stdlib (Go): upgrade to 1.24.2 or later

  ```sh
  go get stdlib@v1.24.2
  ```

- spiral/roadrunner (Packagist): upgrade to 2025.1.0 or later

  ```sh
  composer require spiral/roadrunner:^2025.1.0
  ```


## Technical details

The vulnerability is an HTTP Request Smuggling flaw (CWE-444) originating from the Go Project's net/http package. The package improperly accepts a bare Line Feed (LF) as a line terminator in chunked data lines, which can lead to inconsistent interpretation of requests when the device is used in conjunction with another proxy or server. A remote, unauthenticated attacker can exploit this to smuggle requests, potentially capturing authorization tokens from other users' sessions. This allows for administrative account takeover and full control over the device's management interface. Siemens has addressed this in version V2.1.0.

## Affected products

- Siemens SENTRON 7KT PAC1261 Data Manager Before V2.1.0

## Identifiers

- CVE-2025-22871
- GHSA-g9pc-8g42-g6vq
- GO-2025-3563

## Timeline

- 2026-05-12: disclosed: Initial release by Siemens ProductCERT
- 2026-05-14: advisory: CISA republication of advisory ICSA-26-134-14
- 2026-05-12: patched: Siemens released version V2.1.0 to address the issue

## References

- [https://www.cisa.gov/news-events/ics-advisories/icsa-26-134-14](https://www.cisa.gov/news-events/ics-advisories/icsa-26-134-14)

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