CVE-2011-4073: Use-after-free vulnerability in the cryptographic helper handler functionality in Openswan 2.3.0 through 2.6.3

Routine

MEDIUM 4.0DOWNGRADE

CVE-2011-4073 is a medium-severity flaw (CVSS 4.0) affecting openswan. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Use-after-free vulnerability in the cryptographic helper handler functionality in Openswan 2.3.0 through 2.6.36 allows remote authenticated users to cause a denial of service (pluto IKE daemon crash) via vectors related to the (1) quick_outI1_continue and (2) quick_outI1 functions.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.0 (Medium)
EPSS exploit chance	2.1% (top 18%)
CISA exploited list	No
Weakness	CWE-399
Published	2011-11-17
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: xelerance

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2011-11-17 19:55 UTCPublished CVE record published
2026-06-16 23:34 UTCUpdated Record last modified

xelerance openswan DOWNGRADE

Affected: 2.3.0 · 2.3.1 · 2.4.0 · 2.4.1 · 2.4.2 · 2.4.3 · 2.4.4 · 2.4.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.3.0

1. Check installed version

apt-cache policy openswan || rpm -q openswan || openswan --version

2. No fixed release: DOWNGRADE to a release before 2.3.0 (Debian / Ubuntu)

apt-cache madison openswan sudo apt install openswan=<VERSION_BEFORE_2.3.0> sudo apt-mark hold openswan

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openswan sudo dnf downgrade openswan-<VERSION_BEFORE_2.3.0> sudo dnf versionlock add openswan

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2011-4073?

openswan: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2011-4073 being exploited?

CVE-2011-4073 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2011-4073 affect?

CVE-2011-4073 affects openswan. Severity is medium (CVSS 4.0). Use-after-free vulnerability in the cryptographic helper handler functionality in Openswan 2.3.0 through 2.6.36 allows remote authenticated users to cause a denial of service (pluto IKE daemon crash) via vectors related to the (1) quick_out

How urgent is CVE-2011-4073?

Priority 34/100. No elevated risk signals yet.

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References

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