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Fencer Vulns
medium 5.5

CVE-2020-21047 json

The libcpu component which is used by libasm of elfutils version 0.177 (git 47780c9e), suffers from denial-of-service vulnerability caused…

published 2023-08-22 3 y ago modified 2026-10-14 25 d ago also EUVD-2020-13826

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

The libcpu component which is used by libasm of elfutils version 0.177 (git 47780c9e), suffers from denial-of-service vulnerability caused by application crashes due to out-of-bounds write (CWE-787), off-by-one error (CWE-193) and reachable assertion (CWE-617); to exploit the vulnerability, the attackers need to craft certain ELF files which bypass the missing bound checks.

Patch / fix

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens RUGGEDCOM ROX MX5000 V2.17.0
  • Siemens RUGGEDCOM ROX MX5000RE V2.17.0
  • Siemens RUGGEDCOM ROX RX1400 V2.17.0
  • Siemens RUGGEDCOM ROX RX1500 V2.17.0
  • Siemens RUGGEDCOM ROX RX1501 V2.17.0
  • Siemens RUGGEDCOM ROX RX1510 V2.17.0
  • Siemens RUGGEDCOM ROX RX1511 V2.17.0
  • Siemens RUGGEDCOM ROX RX1512 V2.17.0
  • Siemens RUGGEDCOM ROX RX1524 V2.17.0
  • Siemens RUGGEDCOM ROX RX1536 V2.17.0
  • Siemens RUGGEDCOM ROX RX5000 V2.17.0
  • elfutils Debian 14, Debian 13, Debian 12 0.180-1

debian advisories DEBIAN-CVE-2020-21047

  • elfutils Ubuntu 20.04 LTS 0.176-1.1ubuntu0.1
  • elfutils Ubuntu Pro 14.04 LTS 0.158-0ubuntu5.3+esm1
  • elfutils Ubuntu Pro 16.04 LTS 0.165-3ubuntu1.2+esm1
  • elfutils Ubuntu Pro 18.04 LTS 0.170-0.4ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2020-21047

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-23-348-10 updated cvss 5.5

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens RUGGEDCOM ROX MX5000
  • Siemens RUGGEDCOM ROX MX5000RE
  • Siemens RUGGEDCOM ROX RX1400
  • Siemens RUGGEDCOM ROX RX1500
  • Siemens RUGGEDCOM ROX RX1501
  • Siemens RUGGEDCOM ROX RX1510
  • Siemens RUGGEDCOM ROX RX1511
  • Siemens RUGGEDCOM ROX RX1512
  • Siemens RUGGEDCOM ROX RX1524
  • Siemens RUGGEDCOM ROX RX1536
  • Siemens RUGGEDCOM ROX RX5000

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.