CVE-2006-1721: digestmd5.c in the CMU Cyrus Simple Authentication and Security Layer (SASL) library 2.1.18, and possibly other versions before 2.1.21, allo
Noroxi assessment
Priority: Monitor (action score 11/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 2.4% (FIRST EPSS); higher than 84.5% of all records.
- Special conditions such as timing or configuration are required.
- Fixed version: cyrus-sasl2 (Debian:12) 2.1.19.dfsg1-0.2; cyrus-sasl2 (Debian:3.1) 2.1.19-1.5sarge1; cyrus-sasl (Red Hat:enterprise_linux:3::as) 0:2.1.15-15.
Low priority for now. Upgrade to cyrus-sasl2 (Debian:12) 2.1.19.dfsg1-0.2; cyrus-sasl2 (Debian:3.1) 2.1.19-1.5sarge1; cyrus-sasl (Red Hat:enterprise_linux:3::as) 0:2.1.15-15 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
digestmd5.c in the CMU Cyrus Simple Authentication and Security Layer (SASL) library 2.1.18, and possibly other versions before 2.1.21, allows remote unauthenticated attackers to cause a denial of service (segmentation fault) via malformed inputs in DIGEST-MD5 negotiation.
- Published
- Apr 11, 2006
- Updated
- Jun 16, 2026
- EPSS
- 2.4% · 84th percentile
- CWE
- CWE-20
Report tools
Action score
11
Monitor
Low priority for now.
- CVSS
- 10 / 40 · 2.6 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.4%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| cyrus | sasl | cpe:2.3:a:cyrus:sasl |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cyrus sasl2.1.18
- cyrus sasl2.1.18_r1
- cyrus sasl2.1.18_r2
- cyrus sasl2.1.19
- cyrus sasl2.1.20
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | cyrus-sasl2 | before 2.1.19.dfsg1-0.2 | 2.1.19.dfsg1-0.2 |
| Debian:3.1 | cyrus-sasl2 | before 2.1.19-1.5sarge1 | 2.1.19-1.5sarge1 |
| Red Hat:enterprise_linux:3::as | cyrus-sasl | before 0:2.1.15-15 | 0:2.1.15-15 |
| Red Hat:enterprise_linux:3::as | cyrus-sasl-debuginfo | before 0:2.1.15-15 | 0:2.1.15-15 |
| Red Hat:enterprise_linux:3::as | cyrus-sasl-devel | before 0:2.1.15-15 | 0:2.1.15-15 |
| Red Hat:enterprise_linux:3::as | cyrus-sasl-gssapi | before 0:2.1.15-15 | 0:2.1.15-15 |
| Red Hat:enterprise_linux:3::as | cyrus-sasl-md5 | before 0:2.1.15-15 | 0:2.1.15-15 |
| Red Hat:enterprise_linux:3::as | cyrus-sasl-plain | before 0:2.1.15-15 | 0:2.1.15-15 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl | before 0:2.1.19-14 | 0:2.1.19-14 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl-debuginfo | before 0:2.1.19-14 | 0:2.1.19-14 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl-devel | before 0:2.1.19-14 | 0:2.1.19-14 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl-gssapi | before 0:2.1.19-14 | 0:2.1.19-14 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl-md5 | before 0:2.1.19-14 | 0:2.1.19-14 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl-ntlm | before 0:2.1.19-14 | 0:2.1.19-14 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl-plain | before 0:2.1.19-14 | 0:2.1.19-14 |
| Red Hat:enterprise_linux:4::as | cyrus-sasl-sql | before 0:2.1.19-14 | 0:2.1.19-14 |
Same product
cyrus: all recordsOther highest-scoring records for the same primary product.
- CVE-2005-0373Buffer overflow in digestmd5.c CVS release 1.170 (also referred to as digestmda5.c), as used in the DIGEST-MD5 SASL plugin for Cyrus-SASL bu31Monitor
- CVE-2002-2043SQL injection vulnerability in the LDAP and MySQL authentication patch for Cyrus SASL 1.5.24 and 1.5.27 allows remote attackers to execute a30Monitor
- CVE-2004-0884The (1) libsasl and (2) libsasl2 libraries in Cyrus-SASL 2.1.18 and earlier trust the SASL_PATH environment variable to find all available S28Monitor
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 |
|---|---|---|
| debian:cyrus-sasl2 | 2.1.19.dfsg1-0.2 · Debian:12 | Package registry (OSV) |
| red hat:cyrus-sasl | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-sasl-debuginfo | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-sasl-devel | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-sasl-gssapi | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-sasl-md5 | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-sasl-ntlm | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-sasl-plain | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-sasl-sql | 0:2.1.19-14 · Red Hat:enterprise_linux:4::as | 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.
No history yet (it accumulates with the daily EPSS job).
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.
No credits in the CNA record.
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
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- P · the service can be disrupted
- Attack complexity
- High
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- P
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
AV:N/AC:H/Au:N/C:N/I:N/A:P
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.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Change log
- Fix✗ → ✓
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References
Show all references (19 more)Show less
- asg.web.cmu.edu/archive/message.php?mailbox=archive.cyrus-sasl&msg=7775
- labs.musecurity.com/advisories/MU-200604-01.txt
- lists.apple.com/archives/security-announce/2006/Sep/msg00002.html
- lists.grok.org.uk/pipermail/full-disclosure/2006-April/044992.html
- secunia.com/advisories/19618
- secunia.com/advisories/19753
- secunia.com/advisories/19809
- secunia.com/advisories/19825
- secunia.com/advisories/19964
- secunia.com/advisories/20014
- secunia.com/advisories/22187
- secunia.com/advisories/26708
- secunia.com/advisories/26857
- secunia.com/advisories/27237
- secunia.com/advisories/30535
- securitytracker.com/id?1016960
- support.avaya.com/elmodocs2/security/ASA-2007-426.htm
- www.debian.org/security/2006/dsa-1042
- www.gentoo.org/security/en/glsa/glsa-200604-09.xml
Vendor advisories and official records. Exploit/PoC links are deliberately left out.