Strongswan
CVE-2021-41991
HIGH
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Integer overflow checks
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could cause unexpected behavior through arithmetic overflow by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
The in-memory certificate cache in strongSwan before 5.9.4 has a remote integer overflow upon receiving many requests with different certificates to fill the cache and later trigger the replacement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Validate arithmetic operations, use safe integer libraries, check bounds before allocation.
Affects your stack
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Technical ContextAI · show details
This vulnerability is classified as Integer Overflow (CWE-190), which allows attackers to cause unexpected behavior through arithmetic overflow. The in-memory certificate cache in strongSwan before 5.9.4 has a remote integer overflow upon receiving many requests with different certificates to fill the cache and later trigger the replacement of cache entries. The code attempts to select a less-often-used cache entry by means of a random number generator, but this is not done correctly. Remote code execution might be a slight possibility. Affected products include: Strongswan, Debian Debian Linux, Fedoraproject Fedora, Siemens Sinema Remote Connect Server, Siemens Siplus Et 200Sp Cp 1542Sp-1 Irc Tx Rail Firmware. Version information: before 5.9.4.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
The in-memory certificate cache in strongSwan before 5.9.4 has a remote integer overflow upon receiving many requests with different certificates to fill the cache and later trigger the replacement of cache entries. The code attempts to select a less-often-used cache entry by means of a random number generator, but this is not done correctly. Remote code execution might be a slight possibility.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Integer overflow occurs when an arithmetic operation produces a result that exceeds the maximum value a given integer type can store.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Affected Products (CPE)NVD
More in Strongswan
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strongSwan 5.2.2 and 5.3.0 allows remote attackers to cause a denial of service (daemon crash) or execute arbitrary code
strongSwan before 5.9.12 has a buffer overflow and possible unauthenticated remote code execution via a DH public value
strongSwan 5.9.8 and 5.9.9 potentially allows remote code execution because it uses a variable named "public" for two di
The is_asn1 function in strongSwan 4.1.11 through 5.0.4 does not properly validate the return value of the asn1_length f
The gmp plugin in strongSwan before 5.5.3 does not properly validate RSA public keys before calling mpz_powm_sec, which
The ASN.1 parser in strongSwan before 5.5.3 improperly handles CHOICE types when the x509 plugin is enabled, which allow
The gmp plugin in strongSwan before 5.6.0 allows remote attackers to cause a denial of service (NULL pointer dereference
The GMP Plugin in strongSwan 4.2.0 through 4.6.3 allows remote attackers to bypass authentication via a (1) empty or (2)
Use-after-free in strongSwan's IKEv2 Multi-Key Exchange (Multi-KE, RFC 9370) implementation is triggered when two authen
Denial of service via infinite loop in strongSwan's x509 plugin affects all deployments that process X.509 attribute cer
Denial of service via NULL-pointer dereference in strongSwan's x509 plugin affects versions 4.2.0 through 6.0.x, trigger
Exploit-DB