CVE-2005-0039

CVE-2005-0039 is a medium-severity vulnerability in Nissc Ipsec with a CVSS 2.0 base score of 6.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

Certain configurations of IPsec, when using Encapsulating Security Payload (ESP) in tunnel mode, integrity protection at a higher layer, or Authentication Header (AH), allow remote attackers to decrypt IPSec communications by modifying the outer packet in ways that cause plaintext data from the inner packet to be returned in ICMP messages, as demonstrated using bit-flipping attacks and (1) Destination Address Rewriting, (2) a modified header length that causes portions of the packet to be interpreted as IP Options, or (3) a modified protocol field and source address.

Frequently asked questions

What is CVE-2005-0039?
Certain configurations of IPsec, when using Encapsulating Security Payload (ESP) in tunnel mode, integrity protection at a higher layer, or Authentication Header (AH), allow remote attackers to decrypt IPSec communications by modifying the outer packet in ways that cause plaintext data from the inner packet to be returned in ICMP messages, as demonstrated using bit-flipping attacks and (1) Destination Address Rewriting, (2) a modified header length that causes portions of the packet to be interpreted as IP Options, or (3) a modified protocol field and source address.
How severe is CVE-2005-0039?
CVE-2005-0039 has a CVSS 2.0 base score of 6.4, rated medium severity.
Is CVE-2005-0039 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2005-0039?
CVE-2005-0039 affects Nissc Ipsec. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2005-0039?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2005-0039 published?
CVE-2005-0039 was published on 2005-05-10 and last updated on 2026-06-16.

References

Affected products (1)