SB2026092245 - Debian update for strongswan
Published: September 22, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 11 vulnerabilities.
1) Use of Uninitialized Variable (CVE-ID: CVE-2026-78123)
CWE-ID: CWE-457 - Use of Uninitialized Variable
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use of uninitialized stack variables in the openssl plugin when processing PKCS#7 signerInfo or recipientInfo structures encoded with subjectKeyIdentifier. A remote attacker can send a crafted IKEv1 message containing such a structure to cause a denial of service.
2) Memory leak (CVE-ID: CVE-2026-78124)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause memory leaks.
The vulnerability exists due to missing cleanup in the openssl plugin's PKCS#7 implementation when enumerating certificates in PKCS#7/CMS containers. A remote attacker can send a PKCS#7 container containing one or more certificates to cause memory leaks.
Exploitation is possible before authentication through IKEv1 certificate payloads and requires at least two messages.
3) NULL pointer dereference (CVE-ID: CVE-2026-78126)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a missing state check in the eap-aka plugin when processing an AKA-Synchronization-Failure message before issuing an AKA-Challenge. A remote attacker can send an unexpected AKA-Synchronization-Failure message to cause a denial of service.
The issue occurs when the request_identity option is enabled, which is the default configuration.
4) Memory leak (CVE-ID: CVE-2026-78127)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a memory leak in libcharon IKE message stringification when processing crafted IKE messages whose string representations exceed a fixed-size buffer. A remote attacker can send a large number of specially crafted IKE messages to cause a denial of service.
Built-in denial-of-service protections slow memory exhaustion but do not prevent it entirely, particularly on systems with tight memory constraints.
5) Unchecked Input for Loop Condition (CVE-ID: CVE-2026-78129)
CWE-ID: CWE-606 - Unchecked Input for Loop Condition
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to missing bounds validation of PKCS#5 parameters in the PKCS#5 implementation in libstrongswan when processing an encrypted PKCS#7 container received via an IKEv1 certificate payload. A remote attacker can send a crafted encrypted PKCS#7 container to cause a denial of service.
Remote exploitation requires the pkcs7 plugin to be loaded and IKEv1 to be accepted.
6) NULL pointer dereference (CVE-ID: CVE-2026-78130)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a null pointer dereference in the x509 plugin's attribute certificate validation when validating an X.509 attribute certificate without an issuerName field or AuthorityKeyIdentifier extension. A remote attacker can submit a specially crafted attribute certificate to cause a crash.
Exploitation requires the x509 and acert plugins to be loaded.
7) Memory leak (CVE-ID: CVE-2026-78131)
CWE-ID: CWE-401 - Missing release of memory after effective lifetime
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a memory leak in the x509 plugin's parse_directoryName() function when processing multiple GeneralName entries in the Holder or Issuer fields of an X.509 attribute certificate. A remote attacker can send a crafted X.509 attribute certificate in an IKEv2 CERT payload to cause a denial of service.
8) Infinite loop (CVE-ID: CVE-2026-78132)
CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an infinite loop in the x509 plugin's ietfAttrSyntax ASN.1 parser when parsing a crafted X.509 attribute certificate received in an IKEv2 CERT payload. A remote attacker can send a crafted attribute certificate containing an unexpected or malformed attribute value to cause a denial of service.
Only installations that load the x509 plugin are affected.
9) Use-after-free (CVE-ID: CVE-2026-78133)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 7.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to use-after-free in libcharon's IKEv2 rekeying collision handling when processing IKE or Child SA rekeying collisions involving multiple key exchanges. A remote user can delay or withhold a CREATE_CHILD_SA response and provide missing or invalid KE payloads to execute arbitrary code.
Successful exploitation requires correctly controlling two indirections.
10) Authentication Bypass by Spoofing (CVE-ID: CVE-2026-78134)
CWE-ID: CWE-290 - Authentication Bypass by Spoofing
CVSSv4: 7.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to bypass authorization controls by impersonating another user.
The vulnerability exists due to improper authentication of inner EAP identities in the eap-peap and eap-ttls plugins when processing tunneled EAP authentication. A remote user can authenticate with valid credentials while claiming another user's identity during the outer EAP-Identity exchange to bypass authorization controls by impersonating another user.
Exploitation requires the use of EAP-PEAP or EAP-TTLS tunneling authentication protocols.
11) Improper Authentication (CVE-ID: CVE-2026-78135)
CWE-ID: CWE-287 - Improper Authentication
CVSSv4: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to establish a usable Child SA before authentication completes.
The vulnerability exists due to improper state validation in libcharon's task manager when processing CREATE_CHILD_SA requests on unestablished IKE SAs. A remote attacker can send a CREATE_CHILD_SA request during EAP authentication to establish a usable Child SA before authentication completes.
Exploitation requires EAP authentication and either no configured IP address pool or an explicit remote traffic selector.
Remediation
Install update from vendor's website.