CVE-2022-42898
HighCVSS 8.8Exploitation Probability (EPSS)
Very high risk94th percentile - higher than 94% of all known CVEs
Summary
PAC parsing in MIT Kerberos 5 (aka krb5) before 1.19.4 and 1.20.x before 1.20.1 has integer overflows that may lead to remote code execution (in KDC, kadmind, or a GSS or Kerberos application server) on 32-bit platforms (which have a resultant heap-based buffer overflow), and cause a denial of service on other platforms. This occurs in krb5_pac_parse in lib/krb5/krb/pac.c. Heimdal before 7.7.1 has "a similar bug."
Risk Assessment
On 32-bit platforms, an attacker may remotely execute arbitrary code in critical authentication services, potentially leading to full system compromise; on other platforms, it may cause a denial of service.
Recommendation
Update MIT Kerberos to version 1.19.4 or 1.20.1 (or later), and Heimdal to version 7.7.1 or later; prioritize patching on 32-bit platforms.
Other vulnerabilities in MIT Kerberos 5
See all- CVE-2024-37370High
In MIT Kerberos 5 before version 1.21.3, an attacker can modify the Extra Count field of a confidential GSS krb5 wrap token, causing the unwrapped token to appear truncated to the application.
- CVE-2024-37371Critical
In MIT Kerberos 5 before version 1.21.3, an attacker can cause invalid memory reads during GSS message token handling by sending message tokens with invalid length fields.
- CVE-2021-36222High
A vulnerability in the ec_verify function in kdc/kdc_preauth_ec.c in the Key Distribution Center (KDC) of MIT Kerberos 5 before 1.18.4 and 1.19.x before 1.19.2 allows remote attackers to cause a NULL pointer dereference and daemon crash. This occurs because a return value is not properly handled in a certain situation.
- CVE-2020-28196High
MIT Kerberos 5 (aka krb5) before 1.17.2 and 1.18.x before 1.18.3 allows unbounded recursion via an ASN.1-encoded Kerberos message because the lib/krb5/asn.1/asn1_encode.c support for BER indefinite lengths lacks a recursion limit.
- CVE-2026-107778Medium
MIT Kerberos 5 (krb5) through 1.22.2 contains a NULL pointer dereference in make_cred_list() in rd_cred.c that allows authenticated Kerberos clients to crash services by sending mismatched KRB-CRED arrays. Attackers can send forwarded credentials with more tickets than ticket_info entries through gss_accept_sec_context() to crash GSS-API acceptor services, causing denial of service.
- CVE-2026-107708Medium
MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication.
- CVE-2026-40356Medium
In MIT Kerberos 5 (krb5) before 1.22.3, an integer underflow and resultant out-of-bounds read occur if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parse_message.
- CVE-2026-40355Medium
In MIT Kerberos 5 (krb5) before version 1.22.3, there is a NULL pointer dereference when an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parse_nego_message.
- CVE-2025-3576Medium
A vulnerability in the MIT Kerberos implementation allows GSSAPI-protected messages using RC4-HMAC-MD5 to be spoofed due to weaknesses in the MD5 checksum design. If RC4 is preferred over stronger encryption types, an attacker could exploit MD5 collisions to forge message integrity codes.
- CVE-2021-37750Medium
The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5 and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/do_tgs_req.c via a FAST inner body that lacks a server field. This can lead to a crash of the KDC service.
Original NVD description (English source)
PAC parsing in MIT Kerberos 5 (aka krb5) before 1.19.4 and 1.20.x before 1.20.1 has integer overflows that may lead to remote code execution (in KDC, kadmind, or a GSS or Kerberos application server) on 32-bit platforms (which have a resultant heap-based buffer overflow), and cause a denial of service on other platforms. This occurs in krb5_pac_parse in lib/krb5/krb/pac.c. Heimdal before 7.7.1 has "a similar bug."
Vulnerability data from NVD (NIST) · CISA KEV · EPSS