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Fencer Vulns
medium 5.3

CVE-2025-27587 json

OpenSSL 3.0.0 through 3.3.2 on the PowerPC architecture is vulnerable to a Minerva attack, exploitable by measuring the time of signing of…

published 2025-06-16 16 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-18430

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

OpenSSL 3.0.0 through 3.3.2 on the PowerPC architecture is vulnerable to a Minerva attack, exploitable by measuring the time of signing of random messages using the EVP_DigestSign API, and then using the private key to extract the K value (nonce) from the signatures. Next, based on the bit size of the extracted nonce, one can compare the signing time of full-sized nonces to signatures that used smaller nonces, via statistical tests. There is a side-channel in the P-364 curve that allows private key extraction (also, there is a dependency between the bit size of K and the size of the side channel). NOTE: This CVE is disputed because the OpenSSL security policy explicitly notes that any side channels which require same physical system to be detected are outside of the threat model for the software. The timing signal is so small that it is infeasible to be detected without having the attacking process running on the same physical system.

Patch / fix

  • openssl Debian 14, Debian 13 3.5.0-1

debian advisories DEBIAN-CVE-2025-27587

  • openssl-3 SLE Module for Basesystem 15 SP7 3.2.3-150700.5.10.1
  • openssl-3 SLE Module for Basesystem 15 SP7 3.2.3-150700.5.5.1
  • openssl-3 Linux Micro 6.0 3.1.4-8.1
  • openssl-3 Linux Micro 6.1 3.1.4-slfo.1.1_5.1
  • openssl-3 SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 3.1.4-150600.5.27.1

suse advisories SUSE-SU-2025:02236-1SUSE-SU-2025:02042-1SUSE-SU-2025:20406-1SUSE-SU-2025:20417-1SUSE-SU-2025:1550-1

  • openssl-3 openSUSE Tumbleweed 3.5.0-3.1

opensuse advisories openSUSE-SU-2025:15183-1

Vendor advisories

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

cisa ICSA-26-043-06 updated cvss 5.3

Siemens SINEC OS

  • Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) < 3.3
    affected: fixed in V3.3 support.industry.siemens.com
  • Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family < 3.3
    affected: fixed in V3.3
  • Siemens SCALANCE XCH328 (6GK5328-4TS01-2EC2) < 3.3 Siemens SCALANCE XCM324 (6GK5324-8TS01-2AC2) < 3.3 Siemens SCALANCE XCM328 (6GK5328-4TS01-2AC2) < 3.3 Siemens SCALANCE XCM332 (6GK5332-0GA01-2AC2) < 3.3 Siemens SCALANCE XRH334 (24 V DC, 8xFO, CC) (6GK5334-2TS01-2ER3) < 3.3 Siemens SCALANCE XRM334 (2x230 V AC, 8xFO) (6GK5334-2TS01-4AR3) < 3.3
    +8 more products
    Siemens SCALANCE XRM334 (2x230 V AC, 12xFO) (6GK5334-3TS01-4AR3) < 3.3 Siemens SCALANCE XRM334 (2x230V AC, 2x10G, 24xSFP, 8xSFP+) (6GK5334-5TS01-4AR3) < 3.3 Siemens SCALANCE XRM334 (24 V DC, 8xFO) (6GK5334-2TS01-2AR3) < 3.3 Siemens SCALANCE XRM334 (24 V DC, 12xFO) (6GK5334-3TS01-2AR3) < 3.3 Siemens SCALANCE XRM334 (24V DC, 2x10G, 24xSFP, 8xSFP+) (6GK5334-5TS01-2AR3) < 3.3 Siemens SCALANCE XRM334 (230 V AC, 8xFO) (6GK5334-2TS01-3AR3) < 3.3 Siemens SCALANCE XRM334 (230 V AC, 12xFO) (6GK5334-3TS01-3AR3) < 3.3 Siemens SCALANCE XRM334 (230V AC, 2x10G, 24xSFP, 8xSFP+) (6GK5334-5TS01-3AR3) < 3.3
    affected: fixed in V3.3 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
none
Automatable
no
Technical impact
partial
Assessed
16 mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

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.