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CVE-2001-0554· NVD / CVE Program· CNA mitre

Buffer overflow in BSD-based telnetd telnet daemon on various operating systems allows remote attackers to execute arbitrary commands via a

Buffer overflow in BSD-based telnetd telnet daemon on various operating systems allows remote attackers to execute arbitrary commands via a set of options including AYT (Are You There), which is not properly handled by the telrcv function.

CriticalCVSS 10.0 · v2.0—Proof of concept No fix recorded
Published
Aug 14, 2001
Updated
Jun 16, 2026
EPSS
38.7% · 99th percentile
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Report tools

JSON

Action score

52

Plan

Add it to your regular patch cycle.

CVSS
40 / 40 · 10.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
12 / 30 · 38.7%

Affected systems

VendorProduct
mitkerberos
mitkerberos 5
netkitlinux netkit
sgiirix
freebsdfreebsd
ibmaix
netbsdnetbsd
openbsdopenbsd
sunsolaris
sunsunos
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux2.2
  • freebsd freebsd2.0
  • freebsd freebsd2.0.1
  • freebsd freebsd2.0.5
  • freebsd freebsd2.1
  • freebsd freebsd2.1.0
  • freebsd freebsd2.1.5
  • freebsd freebsd2.1.6
  • freebsd freebsd2.1.6.1
  • freebsd freebsd2.1.7
  • freebsd freebsd2.1.7.1
  • freebsd freebsd2.2
  • freebsd freebsd2.2.1
  • freebsd freebsd2.2.2
  • freebsd freebsd2.2.3
  • freebsd freebsd2.2.4
  • freebsd freebsd2.2.5
  • freebsd freebsd2.2.6
  • freebsd freebsd2.2.7
  • freebsd freebsd2.2.8

Same product

mit: all records

Other highest-scoring records for the same primary product.

  • CVE-2004-0523Multiple buffer overflows in krb5_aname_to_localname for MIT Kerberos 5 (krb5) 1.3.3 and earlier allow remote attackers to execute arbitrary
    43Plan
  • CVE-2009-4212Multiple integer underflows in the (1) AES and (2) RC4 decryption functionality in the crypto library in MIT Kerberos 5 (aka krb5) 1.3 throu
    42Plan
  • CVE-2010-0283The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.7 before 1.7.2, and 1.8 alpha, allows remote attackers to cause a denial of
    32Monitor
  • CVE-2018-5709An issue was discovered in MIT Kerberos 5 (aka krb5) through 1.16.
    31Monitor
  • CVE-2003-0139Certain weaknesses in the implementation of version 4 of the Kerberos protocol (krb4) in the krb5 distribution, when triple-DES keys are use
    31Monitor
  • CVE-2003-0138Version 4 of the Kerberos protocol (krb4), as used in Heimdal and other packages, allows an attacker to impersonate any principal in a realm
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entryremote2001-07-18

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.

  1. First PoC-27 d
  2. Published
  3. TodaySep 30, 2026+9179 d
EPSS, last 120 days+1% in 7 days

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 researchers

Finders, 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

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • No special conditions are required; it is repeatable.

If successful

Confidentiality
C · data can be read
Integrity
C · data or configuration can be modified
Availability
C · the service can be disrupted
Attack complexity
Low
Confidentiality impact
C
Integrity impact
C
Availability impact
C

Weakness class (CWE)

CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

nvd-primary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
char buf[256];memcpy(buf, pkt->data, pkt->len);

Fixed

c
char buf[256];if (pkt->len > sizeof(buf)) {  return -EINVAL;}memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; 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

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records