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PatchSiren cyber security CVE debrief

CVE-2025-0725 Siemens CVE debrief

CVE-2025-0725 is a high-severity memory-corruption issue in the libcurl/zlib handling path described by Siemens and CISA. In affected Siemens industrial products, automatic gzip decompression of HTTP content-encoded responses can trigger an attacker-controlled integer overflow and then a buffer overflow. Siemens and CISA identify update guidance for affected products, with remediation to V3.3 or later.

Vendor
Siemens
Product
RUGGEDCOM RST2428P (6GK6242-6PA00)
CVSS
HIGH 7.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-01-28
Original CVE updated
2026-02-25
Advisory published
2026-01-28
Advisory updated
2026-02-25

Who should care

Operators and maintainers of Siemens industrial networking and OT devices listed in the advisory, especially environments running SINEC OS firmware on RUGGEDCOM RST2428P and related SCALANCE product lines. This matters most where devices may process untrusted HTTP traffic or rely on the affected libcurl/zlib combination.

Technical summary

The issue is described as occurring when libcurl is configured for automatic gzip decompression via CURLOPT_ACCEPT_ENCODING and uses zlib 1.2.0.3 or older. Under those conditions, an attacker-controlled integer overflow can cause libcurl to write beyond a buffer, creating a buffer overflow condition. The CVSS v3.1 vector supplied is AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L, which indicates network reachability, low complexity, no privileges, and no user interaction.

Defensive priority

High

Recommended defensive actions

  • Apply the Siemens remediation and update affected devices to V3.3 or later.
  • Inventory Siemens products against the advisory’s affected product list and verify whether SINEC OS firmware is in use.
  • Reduce exposure of affected OT devices by segmenting networks and limiting unnecessary HTTP access to managed interfaces.
  • Follow CISA industrial control system defense-in-depth and recommended practices while patching is being planned or deployed.

Evidence notes

Source evidence comes from CISA CSAF advisory ICSA-26-043-06 and Siemens ProductCERT advisory SSA-089022. The supplied advisory text states that automatic gzip decompression of content-encoded HTTP responses with CURLOPT_ACCEPT_ENCODING, using zlib 1.2.0.3 or older, can lead to an attacker-controlled integer overflow and buffer overflow. The remediation field recommends updating to V3.3 or later for the affected product sets. CISA published the advisory on 2026-01-28 and republished/updated it on 2026-02-12, 2026-02-24, and 2026-02-25.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-0725 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-0725

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2025-0725 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-0725

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26-043-06.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-089022.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-089022.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-26-043-06

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-alerts/ics-alert-10-301-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/resources-tools/resources/ics-recommended-practices

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/topics/industrial-control-systems

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf

    Reference

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.