CVE-2022-4450 | Double free after calling PEM_read_bio_ex

The function PEM_read_bio_ex() reads a PEM file from a BIO and parses and decodes the "name" (e.g. "CERTIFICATE"), any header data and the payload data. If the function succeeds then the "name_out", "header" and "data" arguments are populated with pointers to buffers containing the relevant decoded data. The caller is responsible for freeing those buffers. It is possible to construct a PEM file that results in 0 bytes of payload data. In this case PEM_read_bio_ex() will return a failure code but will populate the header argument with a pointer to a buffer that has already been freed. If the caller also frees this buffer then a double free will occur. This will most likely lead to a crash. This could be exploited by an attacker who has the ability to supply malicious PEM files for parsing to achieve a denial of service attack. The functions PEM_read_bio() and PEM_read() are simple wrappers around PEM_read_bio_ex() and therefore these functions are also directly affected. These functions are also called indirectly by a number of other OpenSSL functions including PEM_X509_INFO_read_bio_ex() and SSL_CTX_use_serverinfo_file() which are also vulnerable. Some OpenSSL internal uses of these functions are not vulnerable because the caller does not free the header argument if PEM_read_bio_ex() returns a failure code. These locations include the PEM_read_bio_TYPE() functions as well as the decoders introduced in OpenSSL 3.0. The OpenSSL asn1parse command line application is also impacted by this issue.

Published: 2023-02-08 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2022-4450 is rated High Risk (69/100): CVSS High severity, with high exploitation likelihood (EPSS 20.44%, 97th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +20.33% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2022-4450

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.12% 20.44% +20.33%
2 2025-11-21 1.52% 0.12% -1.40%
3 2025-11-18 1.52%

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-4450

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2022-4450

GitHub Security Advisory for CVE-2022-4450

GHSA-v5w6-wcm8-jm4q · Severity: high · Ecosystem: rust — openssl-src contains Double free after calling `PEM_read_bio_ex`

OS Trackers for CVE-2022-4450

vendor priority summary link
alpine CVE-2022-4450: 2 source package rows (openssl, openssl1.1-compat); 93 state rows across 10 repos (3.17-community, 3.17-main, 3.18-community, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-community, edge-main); fixed 10, open 83. https://security.alpinelinux.org/vuln/CVE-2022-4450
debian not yet assigned CVE-2022-4450 not yet assigned priority: Debian including 1 source packages (openssl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2022-4450
gentoo normal CVE-2022-4450: 1 GLSA(s) (202402-08), 1 atom(s) (dev-libs/openssl); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2022-4450
redhat medium https://access.redhat.com/security/cve/CVE-2022-4450
suse medium CVE-2022-4450 severity moderate: SUSE including 525 source package names (0.23.0.3.2.368:libopenssl1_1-1.1.1d-150200.11.57.1, 0.23.0.3.2.368:libopenssl1_1-hmac-1.1.1d-150200.11.57.1, …), 1166 product×package rows across 251 product lines (Container bci/bci-init, Container bci/dotnet-aspnet, … (251 product lines)): Fixed 834, Known Not Affected 203, Known Affected 129. https://www.suse.com/security/cve/CVE-2022-4450/
ubuntu medium CVE-2022-4450 medium priority: Ubuntu including 4 source packages (edk2, nodejs, openssl, openssl1.0), 46 status rows across 13 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 19, released 13, needs-triage 6, DNE 5, ignored 3. https://ubuntu.com/security/CVE-2022-4450

Affected software / configurations for CVE-2022-4450

Vendor Product Version Raw CPE
openssl openssl >= 1.1.1, < 1.1.1t cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl >= 3.0.0, < 3.0.8 cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 4.0.0, < 4.3.16 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*
stormshield stormshield_network_security >= 4.4.0, < 4.6.3 cpe:2.3:a:stormshield:stormshield_network_security:*:*:*:*:*:*:*:*

References for CVE-2022-4450

cvelogic Threat Intelligence