CVE-2025-3576

Kerberos is a network authentication protocol. It is designed to provide strong authentication for client/server applications by using secret-key cryptography.

Security Fix(es):

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. This may lead to unauthorized message tampering.(CVE-2025-3576)

Kerberos is a network authentication protocol. It is designed to provide strong authentication for client/server applications by using secret-key cryptography.

Security Fix(es):

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. This may lead to unauthorized message tampering.(CVE-2025-3576)

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es):

• krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions (CVE-2025-3576)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es):

• krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions (CVE-2025-3576)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es):

• krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions (CVE-2025-3576)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

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. This may lead to unauthorized message tampering.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es):

• krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions (CVE-2025-3576)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es):

• krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions (CVE-2025-3576)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es):

• krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions (CVE-2025-3576)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

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. This may lead to unauthorized message tampering.

• CVE-2025-3576: possible spoofing of GSSAPI-protected messages using RC4-HMAC-MD5

• CVE-2025-3576: possible spoofing of GSSAPI-protected messages using RC4-HMAC-MD5

• SECURITY UPDATE: prevent spoofing vulnerability in GSSAPI-protected messages using RC4-HMAC-MD5 due to weaknesses in MD5 checksum design
  • debian/patches/CVE-2025-3576: don't issue session keys with deprecated enctypes. Updates tests.
  • CVE-2025-3576

• SECURITY UPDATE: prevent spoofing vulnerability in GSSAPI-protected messages using RC4-HMAC-MD5 due to weaknesses in MD5 checksum design
  • debian/patches/CVE-2025-3576: don't issue session keys with deprecated enctypes. Updates tests.
  • CVE-2025-3576

• CVE-2025-3576: prevent spoofing vulnerability in GSSAPI-protected messages using RC4-HMAC-MD5 due to weaknesses in MD5 checksum design
• CVE-2025-24528: prevent overflow when calculating ulog block size

• CVE-2025-24528: prevent overflow when calculating ulog block size
• CVE-2025-3576: don't issue session keys with deprecated enctypes (RC4-HMAC-MD5 spoofing)
• CVE-2026-40355: fix NULL pointer dereference in NegoEx parse_nego_message
• CVE-2026-40356: fix integer underflow in NegoEx parse_message header_len
• CVE-2023-36054: ensure array count consistency in kadm5 RPC to prevent freeing uninitialized pointers in _xdr_kadm5_principal_ent_rec

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. This may lead to unauthorized message tampering.

CVE-2025-3576, 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. This may lead to unauthorized message tampering. CVE-2026-40355, there is a NULL pointer dereference 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, causing the process to terminate in parse_nego_message. CVE-2026-40356, there is an integer underflow and resultant out-of-bounds read 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.

Root has patched CVE-2025-3576 in the rootio-krb5 package for Root:Debian:12. Multiple fixed versions available.

This update for krb5 fixes the following issues:

• CVE-2025-3576: weakness in the MD5 checksum design allows for spoofing of GSSAPI-protected messages that are using RC4-HMAC-MD5 (bsc#1241219).

Krb5, as a very old protocol, supported quite a number of ciphers that are not longer up to current cryptographic standards.

To avoid problems with those, SUSE has by default now disabled those alorithms.

The following algorithms have been removed from valid krb5 enctypes:

• des3-cbc-sha1
• arcfour-hmac-md5

To reenable those algorithms, you can use allow options in krb5.conf:

[libdefaults]
allow_des3 = true
allow_rc4 = true

This update for krb5 fixes the following issues:

• CVE-2025-3576: weakness in the MD5 checksum design allows for spoofing of GSSAPI-protected messages that are using RC4-HMAC-MD5 (bsc#1241219).

Krb5 as very old protocol supported quite a number of ciphers that are not longer up to current cryptographic standards.

To avoid problems with those, SUSE has by default now disabled those alorithms.

The following algorithms have been removed from valid krb5 enctypes:

• des3-cbc-sha1
• arcfour-hmac-md5

To reenable those algorithms, you can use allow options in krb5.conf:

[libdefaults] allow_des3 = true allow_rc4 = true

to reenable them.

This update for krb5 fixes the following issues:

• CVE-2025-3576: Fixed Kerberos RC4-HMAC-MD5 Checksum Vulnerability (bsc#1241219)

This update for krb5 fixes the following issues:

• CVE-2025-3576: weakness in the MD5 checksum design allows for spoofing of GSSAPI-protected messages that are using RC4-HMAC-MD5 (bsc#1241219).

Krb5 as very old protocol supported quite a number of ciphers that are not longer up to current cryptographic standards.

To avoid problems with those, SUSE has by default now disabled those alorithms.

The following algorithms have been removed from valid krb5 enctypes:

• des3-cbc-sha1
• arcfour-hmac-md5

To reenable those algorithms, you can use allow options in krb5.conf:

[libdefaults] allow_des3 = true allow_rc4 = true

to reenable them.

This update for krb5 fixes the following issues:

• CVE-2025-3576: weakness in the MD5 checksum design allows for spoofing of GSSAPI-protected messages that are using RC4-HMAC-MD5 (bsc#1241219).

Krb5 as very old protocol supported quite a number of ciphers that are not longer up to current cryptographic standards.

To avoid problems with those, SUSE has by default now disabled those alorithms.

The following algorithms have been removed from valid krb5 enctypes:

• des3-cbc-sha1
• arcfour-hmac-md5

To reenable those algorithms, you can use allow options in krb5.conf:

[libdefaults] allow_des3 = true allow_rc4 = true

to reenable them.

This update for krb5 fixes the following issues:

• CVE-2025-3576: weakness in the MD5 checksum design allows for spoofing of GSSAPI-protected messages that are using RC4-HMAC-MD5 (bsc#1241219).

Krb5 as very old protocol supported quite a number of ciphers that are not longer up to current cryptographic standards.

To avoid problems with those, SUSE has by default now disabled those alorithms.

The following algorithms have been removed from valid krb5 enctypes:

• des3-cbc-sha1
• arcfour-hmac-md5

To reenable those algorithms, you can use allow options in krb5.conf:

[libdefaults] allow_des3 = true allow_rc4 = true

to reenable them.

It was discovered that Kerberos allowed the usage of weak cryptographic standards. An attacker could possibly use this issue to expose sensitive information.

This update introduces the allow_rc4 and allow_des3 configuration options, and disables the usage of RC4 and 3DES ciphers by default. Users are advised to discontinue their usage and upgrade to stronger encryption protocols. If the use of the insecure RC4 and 3DES algorithms is necessary, they can be enabled with the aforementioned configuration options.