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CVE-2023-6237

Excessive time spent checking invalid RSA public keys

Medium5.9EPSS 2.3%
Published
Updated
Reserved
Assigned by
openssl

Description

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.

Scores

CVSS scores of CVE-2023-6237, by who scored it
Scored byCVSSScoreVector
CISA-ADPADP (enrichment)3.1Medium5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Awaiting Analysis3.1Medium5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
2.3% · top 17% of all CVEs (7 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.

Weakness

Affected products

  • OpenSSL · OpenSSL

    • affected 3.0.0 – < 3.0.13
    • affected 3.1.0 – < 3.1.5
    • affected 3.2.0 – < 3.2.1

References (10)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .