Buffer overflow in the slc_add_reply function in various BSD-based Telnet clients, when handling LINEMODE suboptions, allows remote attacker
Buffer overflow in the slc_add_reply function in various BSD-based Telnet clients, when handling LINEMODE suboptions, allows remote attackers to execute arbitrary code via a reply with a large number of Set Local Character (SLC) commands.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 help- Published
- May 2, 2005
- Updated
- Jun 16, 2026
- EPSS
- 8.9% · 95th percentile
- CWE
- —
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Report tools
Action score
33
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 3 / 30 · 8.9%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| ncsa | telnet | cpe:2.3:a:ncsa:telnet |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- ncsa telnetall versions
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | heimdal | before 0.6.3-10 | 0.6.3-10 |
| Debian:12 | krb5 | before 1.3.6-2 | 1.3.6-2 |
| Debian:12 | netkit-telnet-ssl | before 0.17.24+0.1-7.1 | 0.17.24+0.1-7.1 |
| Debian:3.0 | heimdal | before 0.4e-7.woody.11 | 0.4e-7.woody.11 |
| Debian:3.0 | krb4 | before 1.1-8-2.4 | 1.1-8-2.4 |
| Debian:3.0 | krb5 | before 1.2.4-5woody8 | 1.2.4-5woody8 |
| Debian:3.0 | netkit-telnet | before 0.17-18woody3 | 0.17-18woody3 |
| Debian:3.0 | netkit-telnet-ssl | before 0.17.17+0.1-2woody4 | 0.17.17+0.1-2woody4 |
| Red Hat:enterprise_linux:3::as | krb5 | before 0:1.2.7-42 | 0:1.2.7-42 |
| Red Hat:enterprise_linux:3::as | krb5-debuginfo | before 0:1.2.7-42 | 0:1.2.7-42 |
| Red Hat:enterprise_linux:3::as | krb5-devel | before 0:1.2.7-42 | 0:1.2.7-42 |
| Red Hat:enterprise_linux:3::as | krb5-libs | before 0:1.2.7-42 | 0:1.2.7-42 |
| Red Hat:enterprise_linux:3::as | krb5-server | before 0:1.2.7-42 | 0:1.2.7-42 |
| Red Hat:enterprise_linux:3::as | krb5-workstation | before 0:1.2.7-42 | 0:1.2.7-42 |
| Red Hat:enterprise_linux:3::as | telnet | before 1:0.17-26.EL3.2 | 1:0.17-26.EL3.2 |
| Red Hat:enterprise_linux:3::as | telnet-debuginfo | before 1:0.17-26.EL3.2 | 1:0.17-26.EL3.2 |
| Red Hat:enterprise_linux:3::as | telnet-server | before 1:0.17-26.EL3.2 | 1:0.17-26.EL3.2 |
| Red Hat:enterprise_linux:4::as | krb5 | before 0:1.3.4-12 | 0:1.3.4-12 |
| Red Hat:enterprise_linux:4::as | krb5-debuginfo | before 0:1.3.4-12 | 0:1.3.4-12 |
| Red Hat:enterprise_linux:4::as | krb5-devel | before 0:1.3.4-12 | 0:1.3.4-12 |
| Red Hat:enterprise_linux:4::as | krb5-libs | before 0:1.3.4-12 | 0:1.3.4-12 |
| Red Hat:enterprise_linux:4::as | krb5-server | before 0:1.3.4-12 | 0:1.3.4-12 |
| Red Hat:enterprise_linux:4::as | krb5-workstation | before 0:1.3.4-12 | 0:1.3.4-12 |
| Red Hat:enterprise_linux:4::as | telnet | before 1:0.17-31.EL4.2 | 1:0.17-31.EL4.2 |
+2
Same product
ncsa: all recordsOther highest-scoring records for the same primary product.
- CVE-2005-0468Heap-based buffer overflow in the env_opt_add function in telnet.c for various BSD-based Telnet clients allows remote attackers to execute a38Monitor
- CVE-1999-1090The default configuration of NCSA Telnet package for Macintosh and PC enables FTP, even though it does not include an "ftp=yes" line, which 30Monitor
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:heimdal | 0.6.3-10 · Debian:12 | Package registry (OSV) |
| debian:krb4 | 1.1-8-2.4 · Debian:3.0 | Package registry (OSV) |
| debian:krb5 | 1.3.6-2 · Debian:12 | Package registry (OSV) |
| debian:netkit-telnet | 0.17-18woody3 · Debian:3.0 | Package registry (OSV) |
| debian:netkit-telnet-ssl | 0.17.24+0.1-7.1 · Debian:12 | Package registry (OSV) |
| red hat:krb5 | 0:1.2.7-42 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:krb5-debuginfo | 0:1.2.7-42 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:krb5-devel | 0:1.2.7-42 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:krb5-libs | 0:1.2.7-42 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:krb5-server | 0:1.2.7-42 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:krb5-workstation | 0:1.2.7-42 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:telnet | 1:0.17-26.EL3.2 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:telnet-debuginfo | 1:0.17-26.EL3.2 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:telnet-server | 1:0.17-26.EL3.2 · Red Hat:enterprise_linux:3::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.
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.
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
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- P · data can be read
- Integrity
- P · data or configuration can be modified
- Availability
- P · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- P
- Integrity impact
- P
- Availability impact
- P
Weakness class (CWE)
—
CVSS vector
AV:N/AC:L/Au:N/C:P/I:P/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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:01.telnet.asc
- ftp://patches.sgi.com/support/free/security/advisories/20050405-01-P
- secunia.com/advisories/14745
- secunia.com/advisories/17899
- sunsolve.sun.com/search/document.do?assetkey=1-26-101665-1
- sunsolve.sun.com/search/document.do?assetkey=1-26-101671-1
- sunsolve.sun.com/search/document.do?assetkey=1-26-57755-1
- sunsolve.sun.com/search/document.do?assetkey=1-26-57761-1
- web.mit.edu/kerberos/advisories/MITKRB5-SA-2005-001-telnet.txt
- www.debian.de/security/2005/dsa-731
- www.debian.org/security/2005/dsa-697
- www.debian.org/security/2005/dsa-699
- www.debian.org/security/2005/dsa-703
- www.gentoo.org/security/en/glsa/glsa-200503-36.xml
- www.idefense.com/application/poi/display?id=220&type=vulnerabilities
- www.kb.cert.org/vuls/id/291924
- www.mandriva.com/security/advisories?name=MDKSA-2005:061
- www.redhat.com/support/errata/RHSA-2005-327.html
- www.redhat.com/support/errata/RHSA-2005-330.html
- www.securityfocus.com/bid/12918
Vendor advisories and official records. Exploit/PoC links are deliberately left out.