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HuttenlocherTechnologies
HighCVSS 7.55.0% exploit oddsWebsites & servers

CVE-2023-0215

The public API function BIO_new_NDEF is a helper function used for streaming ASN.1 data via a BIO.

The public API function BIO_new_NDEF is a helper function used for streaming ASN.1 data via a BIO. It is primarily used internally to OpenSSL to support the SMIME, CMS and PKCS7 streaming capabilities, but may also be called directly by end user applications. The function receives a BIO from the caller, prepends a new BIO_f_asn1 filter BIO onto the front of it to form a BIO chain, and then returns the new head of the BIO chain to the caller. Under certain conditions, for example if a CMS recipient public key is invalid, the new filter BIO is freed and the function returns a NULL result indicating a failure. However, in this case, the BIO chain is not properly cleaned up and the BIO passed by the caller still retains internal pointers to the previously freed filter BIO. If the caller then goes on to call BIO_pop() on the BIO then a use-after-free will occur. This will most likely result in a crash. This scenario occurs directly in the internal function B64_write_ASN1() which may cause BIO_new_NDEF() to be called and will subsequently call BIO_pop() on the BIO. This internal function is in turn called by the public API functions PEM_write_bio_ASN1_stream, PEM_write_bio_CMS_stream

Description from the National Vulnerability Database, published by openssl-security@openssl.org

What to do: Apply the vendor’s update. The NVD record links to the advisory.

What it means for a small business

OpenSSL runs on web servers, so this is mostly your hosting company's to fix. On shared hosting you can't patch it yourself, but you can ask.

Ask your host whether your server runs it, whether it's updated, and on what date. A good host answers that in a day.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 5.0%, top 8% of all CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

  • Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
  • Server check: what your web server says about itself, and whether that version has known flaws.

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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