Sendmail up to 8.13.7 Mail Header Long Header resource management ⚔ [Disputed]

CVSS Meta Temp Score
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CTI Interest Score
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6.7$0-$5k0.00

Summaryinfo

A vulnerability was found in Sendmail. It has been classified as critical. Affected by this vulnerability is an unknown functionality of the component Mail Header Handler. This manipulation as part of Long Header causes resource management. This vulnerability is tracked as CVE-2006-4434. No exploit exists. There is ongoing doubt regarding the real existence of this vulnerability. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Sendmail (Mail Server Software) and classified as critical. Affected by this vulnerability is an unknown code block of the component Mail Header Handler. The manipulation as part of a Long Header leads to a resource management vulnerability. The CWE definition for the vulnerability is CWE-399. As an impact it is known to affect availability. The summary by CVE is:

Use-after-free vulnerability in Sendmail before 8.13.8 allows remote attackers to cause a denial of service (crash) via a long "header line", which causes a previously freed variable to be referenced. NOTE: the original developer has disputed the severity of this issue, saying "The only denial of service that is possible here is to fill up the disk with core dumps if the OS actually generates different core dumps (which is unlikely)... the bug is in the shutdown code (finis()) which leads directly to exit(3), i.e., the process would terminate anyway, no mail delivery or receiption is affected."

The bug was discovered 08/09/2006. The weakness was disclosed 08/28/2006 by Moritz Jodeit with OpenBSD (Website). The advisory is shared at openbsd.org. This vulnerability is known as CVE-2006-4434 since 08/28/2006. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

After even before and not, there has been an exploit disclosed. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 19 days. During that time the estimated underground price was around $5k-$25k. The real existence of this vulnerability is still doubted at the moment. The vulnerability scanner Nessus provides a plugin with the ID 22706 (Debian DSA-1164-1 : sendmail - programming error), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 74220 (Sendmail Long Header Denial of Service Vulnerability).

Upgrading eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at sendmail.org. The best possible mitigation is suggested to be upgrading to the latest version. A possible mitigation has been published 3 days after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (28662), Tenable (22706), SecurityFocus (BID 19714†), OSVDB (28193†) and Secunia (SA22369†). The entries VDB-2495 and VDB-2496 are pretty similar. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 6.7

VulDB Base Score: 7.5
VulDB Temp Score: 6.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Resource management
CWE: CWE-399 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Proof-of-Concept

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 22706
Nessus Name: Debian DSA-1164-1 : sendmail - programming error
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
Nessus Port: 🔍

OpenVAS ID: 57332
OpenVAS Name: Debian Security Advisory DSA 1164-1 (sendmail)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Patch: sendmail.org

Timelineinfo

08/09/2006 🔍
08/25/2006 +16 days 🔍
08/25/2006 +0 days 🔍
08/25/2006 +0 days 🔍
08/25/2006 +0 days 🔍
08/28/2006 +3 days 🔍
08/28/2006 +0 days 🔍
08/28/2006 +0 days 🔍
08/28/2006 +0 days 🔍
08/29/2006 +0 days 🔍
08/31/2006 +2 days 🔍
09/05/2006 +5 days 🔍
10/11/2006 +36 days 🔍
10/14/2006 +3 days 🔍
06/16/2025 +6820 days 🔍

Sourcesinfo

Advisory: openbsd.org
Researcher: Moritz Jodeit
Organization: OpenBSD
Status: Confirmed
Confirmation: 🔍
Disputed: 🔍

CVE: CVE-2006-4434 (🔍)
GCVE (CVE): GCVE-0-2006-4434
GCVE (VulDB): GCVE-100-2497
X-Force: 28662
SecurityFocus: 19714 - Sendmail Long Header Denial Of Service Vulnerability
Secunia: 22369 - Sun Solaris Sendmail Long Header Denial of Service, Moderately Critical
OSVDB: 28193 - Sendmail Header Processing Overflow DoS
SecurityTracker: 1016753
Vulnerability Center: 12650 - Sendmail Use-after-free Denial of Service via Long Header Line, High
Vupen: ADV-2006-3994

See also: 🔍

Entryinfo

Created: 08/29/2006 17:02
Updated: 06/16/2025 04:11
Changes: 08/29/2006 17:02 (100), 06/24/2019 20:34 (1), 06/16/2025 04:11 (18)
Complete: 🔍
Cache ID: 216:A5B:103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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