In stroke_socket.c in strongSwan before 5.6.3, a missing packet length check could allow a buffer underflow, which may lead to resource exha
In stroke_socket.c in strongSwan before 5.6.3, a missing packet length check could allow a buffer underflow, which may lead to resource exhaustion and denial of service while reading from the socket.
- Published
- May 31, 2018
- Updated
- Jun 16, 2026
- EPSS
- 4.0% · 90th percentile
- CWE
- CWE-124
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Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 4.0%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| strongswan | strongswan | cpe:2.3:a:strongswan:strongswan |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux14.04
- canonical ubuntu linux16.04
- canonical ubuntu linux18.04
- debian debian linux8.0
- debian debian linux9.0
- strongswan strongswanbefore 5.6.3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (certcc). Independent of NVD's CPE analysis and usually ahead of it.
strongSwan strongSwan
- 5.6.3 and later · before 5.6.3affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | strongswan | before 5.6.3-r0 | 5.6.3-r0 |
| Debian:12 | strongswan | before 5.6.3-1 | 5.6.3-1 |
| Debian:8 | strongswan | before 5.2.1-6+deb8u6 | 5.2.1-6+deb8u6 |
| Debian:9 | strongswan | before 5.5.1-4+deb9u2 | 5.5.1-4+deb9u2 |
| openSUSE:Leap 15.0 | strongswan | before 5.6.0-lp150.3.3.1 | 5.6.0-lp150.3.3.1 |
| openSUSE:Leap 15.1 | strongswan | before 5.6.0-lp151.4.3.1 | 5.6.0-lp151.4.3.1 |
| openSUSE:Tumbleweed | strongswan | before 5.9.0-1.9 | 5.9.0-1.9 |
| SUSE:Linux Enterprise Module for Basesystem 15 | strongswan | before 5.6.0-4.3.2 | 5.6.0-4.3.2 |
| SUSE:OpenStack Cloud 7 | strongswan | before 5.1.3-26.13.1 | 5.1.3-26.13.1 |
Same product
strongswan: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-41913strongSwan before 5.9.12 has a buffer overflow and possible unauthenticated remote code execution via a DH public value that exceeds the int40Plan
- CVE-2023-26463strongSwan 5.9.8 and 5.9.9 potentially allows remote code execution because it uses a variable named "public" for two different purposes wit40Plan
- CVE-2015-3991strongSwan 5.2.2 and 5.3.0 allows remote attackers to cause a denial of service (daemon crash) or execute arbitrary code.40Plan
- CVE-2021-45079In strongSwan before 5.9.5, a malicious responder can send an EAP-Success message too early without actually authenticating the client and (37Monitor
- CVE-2026-25075strongSwan 4.5.0 < 6.0.5 EAP-TTLS AVP Parsing Integer Underflow34Monitor
- CVE-2025-62291In the eap-mschapv2 plugin (client-side) in strongSwan before 6.0.3, a malicious EAP-MSCHAPv2 server can send a crafted message of size 6 th32Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:strongswan | 5.6.3-r0 · Alpine:v3.10 | Package registry (OSV) |
| debian:strongswan | 5.6.3-1 · Debian:12 | Package registry (OSV) |
| opensuse:strongswan | 5.6.0-lp150.3.3.1 · openSUSE:Leap 15.0 | Package registry (OSV) |
| suse:strongswan | 5.6.0-4.3.2 · SUSE:Linux Enterprise Module for Basesystem 15 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-124 · Buffer Underwrite ('Buffer Underflow')CVSS vector
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-security-announce/2019-11/msg00077.html
- lists.opensuse.org/opensuse-security-announce/2019-12/msg00001.html
- lists.opensuse.org/opensuse-security-announce/2020-03/msg00047.html
- packetstormsecurity.com/files/172833/strongSwan-VPN-Charon-Server-Buffer-Overflow.html
- www.kb.cert.org/vuls/id/338343
- www.securityfocus.com/bid/104263
- git.strongswan.org/?p=strongswan.git%3Ba=commitdiff%3Bh=0acd1ab4
- security.gentoo.org/glsa/201811-16
- usn.ubuntu.com/3771-1/
- www.debian.org/security/2018/dsa-4229
Vendor advisories and official records. Exploit/PoC links are deliberately left out.