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Fencer Vulns
medium 5.9

CVE-2023-6237 json

Excessive time spent checking invalid RSA public keys

published 2024-04-25 2 y ago modified 2026-11-06 2 d ago also EUVD-2023-58483 , GHSA-hvc4-mjv4-5mw6 , JLSEC-2026-246

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

Issue summary: Checking excessively long invalid RSA public keys may take a long time.

Impact summary: Applications that use the function EVP_PKEY_public_check() to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may lead to a Denial of Service.

When function EVP_PKEY_public_check() is called on RSA public keys, a computation is done to confirm that the RSA modulus, n, is composite. For valid RSA keys, n is a product of two or more large primes and this computation completes quickly. However, if n is an overly large prime, then this computation would take a long time.

An application that calls EVP_PKEY_public_check() and supplies an RSA key obtained from an untrusted source could be vulnerable to a Denial of Service attack.

The function EVP_PKEY_public_check() is not called from other OpenSSL functions however it is called from the OpenSSL pkey command line application. For that reason that application is also vulnerable if used with the '-pubin' and '-check' options on untrusted data.

The OpenSSL SSL/TLS implementation is not affected by this issue.

The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.

Patch / fix

  • julia OpenSSL_jll 3.0.13+0
  • OpenSSL OpenSSL 3.0.13, 3.1.5, 3.2.1
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem V1.1.1
  • Siemens SINEC NMS V3.0 SP1
  • openssl Debian 12 3.0.13-1~deb12u1
  • openssl Debian 14, Debian 13 3.1.5-1

debian advisories DEBIAN-CVE-2023-6237

  • edk2 Ubuntu 24.04 LTS 2024.02-2ubuntu0.6
  • openssl Ubuntu 22.04 LTS 3.0.2-0ubuntu1.14
  • openssl Ubuntu 24.04 LTS 3.0.10-1ubuntu4
  • openssl Ubuntu Pro FIPS-updates 22.04 LTS 3.0.2-0ubuntu1.14+Fips1

ubuntu advisories UBUNTU-CVE-2023-6237

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

  • edk2 RHEL 9 20240524-6.el9_5
  • edk2-ovmf RHEL 9 20240524-6.el9_5
  • edk2-tools RHEL 9 20240524-6.el9_5
  • edk2-aarch64 RHEL 9 20240524-6.el9_5
  • openssl RHEL 9 1:3.0.7-27.el9
  • openssl-libs RHEL 9 1:3.0.7-27.el9
  • openssl-perl RHEL 9 1:3.0.7-27.el9

red hat advisories RHSA-2024:9088RHSA-2024:2447

  • openssl-3 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +7 more 3.0.8-150400.4.49.1
  • openssl-3 SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 3.0.8-150500.5.24.1

suse advisories SUSE-SU-2024:0518-1SUSE-SU-2024:0172-1

  • openssl-3 openSUSE Tumbleweed 3.1.4-3.1

opensuse advisories openSUSE-SU-2024:13633-1

  • edk2-ovmf AlmaLinux 9 20240524-6.el9_5
  • edk2-tools AlmaLinux 9 20240524-6.el9_5
  • edk2-aarch64 AlmaLinux 9 20240524-6.el9_5
  • openssl AlmaLinux 9 1:3.0.7-27.el9
  • openssl-libs AlmaLinux 9 1:3.0.7-27.el9
  • openssl-perl AlmaLinux 9 1:3.0.7-27.el9

almalinux advisories ALSA-2024:9088ALSA-2024:2447

  • edk2 Rocky Linux 9 20240524-6.el9_5.3

rocky linux advisories RLSA-2024:9088

  • openssl Alpine 3.17 3.0.12-r3
  • openssl Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 3.1.4-r4

alpine advisories ALPINE-CVE-2023-6237

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openssl Azure Linux 3.0 3.3.0-1
  • nodejs Azure Linux 3.0 20.14.0-1
  • nodejs18 CBL-Mariner 2.0 18.20.2-1
  • cloud-hypervisor-cvm CBL-Mariner 2.0, Azure Linux 3.0 38.0.72.2-1
  • hvloader CBL-Mariner 2.0 1.0.1-6

azure linux advisories AZL-39946AZL-39961AZL-39968AZL-42688AZL-42727AZL-47670

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

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

red hat product security vex CVE-2023-6237 updated cvss 5.9

openssl: Excessive time spent checking invalid RSA public keys

  • Red Hat CodeReady Linux Builder (v. 9) edk2-ovmf 20240524-6.el9_5, edk2-tools 20240524-6.el9_5, edk2-aarch64 20240524-6.el9_5
    fixed: vendor fix RHSA-2024:9088
  • Red Hat Enterprise Linux AppStream (v. 9) edk2 20240524-6.el9_5, openssl-perl 3.0.7-27.el9, edk2-ovmf 20240524-6.el9_5, edk2-aarch64 20240524-6.el9_5 Red Hat Enterprise Linux BaseOS (v. 9) openssl 3.0.7-27.el9, openssl-libs 3.0.7-27.el9
    fixed: vendor fix RHSA-2024:2447
  • Red Hat Enterprise Linux 6 openssl, openssl-perl Red Hat Enterprise Linux 7 ovmf, OVMF, AAVMF, openssl, openssl-libs, openssl-perl Red Hat Enterprise Linux 8 edk2, shim, openssl, shim-x64, edk2-ovmf, shim-aa64, +5 more Red Hat Enterprise Linux 9 shim, shim-x64, shim-aa64, compat-openssl11 Red Hat Enterprise Linux BaseOS (v. 9) openssl-fips-provider 3.0.7-2.el9 Red Hat JBoss Core Services jbcs-httpd24-openssl
    +1 more products
    Red Hat JBoss Web Server 5 openssl
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-24-102-01 updated cvss 5.9

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    affected: mitigation, no fix available

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

cisa ICSA-25-044-09 updated cvss 5.9

Siemens SCALANCE W700 IEEE 802.11ax

  • Siemens SCALANCE WAB762-1 (6GK5762-1AJ00-6AA0) <V3.0.0 Siemens SCALANCE WAM763-1 (6GK5763-1AL00-7DA0) <V3.0.0 Siemens SCALANCE WAM763-1 (ME) (6GK5763-1AL00-7DC0) <V3.0.0 Siemens SCALANCE WAM763-1 (US) (6GK5763-1AL00-7DB0) <V3.0.0 Siemens SCALANCE WAM766-1 (6GK5766-1GE00-7DA0) <V3.0.0 Siemens SCALANCE WAM766-1 (ME) (6GK5766-1GE00-7DC0) <V3.0.0
    +13 more products
    Siemens SCALANCE WAM766-1 (US) (6GK5766-1GE00-7DB0) <V3.0.0 Siemens SCALANCE WAM766-1 EEC (6GK5766-1GE00-7TA0) <V3.0.0 Siemens SCALANCE WAM766-1 EEC (ME) (6GK5766-1GE00-7TC0) <V3.0.0 Siemens SCALANCE WAM766-1 EEC (US) (6GK5766-1GE00-7TB0) <V3.0.0 Siemens SCALANCE WUB762-1 (6GK5762-1AJ00-1AA0) <V3.0.0 Siemens SCALANCE WUB762-1 iFeatures (6GK5762-1AJ00-2AA0) <V3.0.0 Siemens SCALANCE WUM763-1 (6GK5763-1AL00-3AA0) <V3.0.0 Siemens SCALANCE WUM763-1 (6GK5763-1AL00-3DA0) <V3.0.0 Siemens SCALANCE WUM763-1 (US) (6GK5763-1AL00-3AB0) <V3.0.0 Siemens SCALANCE WUM763-1 (US) (6GK5763-1AL00-3DB0) <V3.0.0 Siemens SCALANCE WUM766-1 (6GK5766-1GE00-3DA0) <V3.0.0 Siemens SCALANCE WUM766-1 (ME) (6GK5766-1GE00-3DC0) <V3.0.0 Siemens SCALANCE WUM766-1 (USA) (6GK5766-1GE00-3DB0) <V3.0.0
    affected: fixed in V3.0.0 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
2 y ago

Exploit prediction

2.30% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia OpenSSL_jll
>=3.0.8+0, <3.0.13+0
3.0.13+0

Affected products

  • OpenSSL OpenSSL
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
  • Siemens SINEC NMS

Classification

Weakness
  • CWE-606 Unchecked Input for Loop Condition
Technology feeds

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.