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Fencer Vulns
medium 6.2

CVE-2019-1736 json

Multiple Cisco UCS-Based Products UEFI Secure Boot Bypass Vulnerability

published 2020-09-23 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-10293

cvss
6.2
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

A vulnerability in the firmware of the Cisco UCS C-Series Rack Servers could allow an authenticated, physical attacker to bypass Unified Extensible Firmware Interface (UEFI) Secure Boot validation checks and load a compromised software image on an affected device. The vulnerability is due to improper validation of the server firmware upgrade images. An attacker could exploit this vulnerability by installing a server firmware version that would allow the attacker to disable UEFI Secure Boot. A successful exploit could allow the attacker to bypass the signature validation checks that are done by UEFI Secure Boot technology and load a compromised software image on the affected device. A compromised software image is any software image that has not been digitally signed by Cisco.

Patch / fix

  • cisco fmc1000-k9_bios 4.0.1f.0
  • cisco fmc1000-k9_firmware 4.0.2h
  • cisco fmc2500-k9_bios 4.0.1f.0
  • cisco fmc2500-k9_firmware 4.0.2h
  • cisco fmc4500-k9_bios 4.0.1f.0
  • cisco fmc4500-k9_firmware 4.0.2h
  • cisco sns-3515-k9_bios 4.0.2d
  • cisco sns-3515-k9_firmware 4.0.2h
  • cisco sns-3595-k9_bios 4.0.2d
  • cisco sns-3595-k9_firmware 4.0.2h
  • cisco sns-3615-k9_bios 4.0.1i
  • cisco sns-3615-k9_firmware 4.0.1g
  • cisco sns-3655-k9_bios 4.0.1i
  • cisco sns-3655-k9_firmware 4.0.1g
  • cisco sns-3695-k9_bios 4.0.1i
  • cisco sns-3695-k9_firmware 4.0.1g
  • cisco tg5004-k9_bios 4.0.2d
  • cisco tg5004-k9_firmware 4.0.2h
  • cisco tg5004-k9-rf_bios 4.0.2d
  • cisco tg5004-k9-rf_firmware 4.0.2h

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
23 mo 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
CNA 3.0 6.2 CVSS:3.0/AV:P/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 6.6 CVSS:3.1/AV:P/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.9 AV:L/AC:M/Au:N/C:C/I:C/A:C

Affected products

  • Cisco Cisco Identity Services Engine Software

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

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.