telnetd in GNU Inetutils through 2.3, MIT krb5-appl through 1.0.3, and derivative works has a NULL pointer dereference via 0xff 0xf7 or 0xff
telnetd in GNU Inetutils through 2.3, MIT krb5-appl through 1.0.3, and derivative works has a NULL pointer dereference via 0xff 0xf7 or 0xff 0xf8. In a typical installation, the telnetd application would crash but the telnet service would remain available through inetd. However, if the telnetd application has many crashes within a short time interval, the telnet service would become unavailable after inetd logs a "telnet/tcp server failing (looping), service terminated" error. NOTE: MIT krb5-appl is not supported upstream but is shipped by a few Linux distributions. The affected code was removed from the supported MIT Kerberos 5 (aka krb5) product many years ago, at version 1.8.
- Published
- Aug 30, 2022
- Updated
- Jun 17, 2026
- EPSS
- 2.1% · 81th percentile
- CWE
- CWE-476
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.1%
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 helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| gnu | inetutils | cpe:2.3:a:gnu:inetutils |
| mit | kerberos 5 | cpe:2.3:a:mit:kerberos_5 |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netkit-telnet project | netkit-telnet | cpe:2.3:a:netkit-telnet_project:netkit-telnet |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- gnu inetutilsup to 2.3 inclusive
- mit kerberos 5up to 1.0.3 inclusive
- netkit-telnet project netkit-telnetup to 0.17 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | inetutils | before 2:1.9.4-7+deb10u2 | 2:1.9.4-7+deb10u2 |
| Debian:12 | inetutils | before 2:2.3-5 | 2:2.3-5 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP3 | telnet | before 1.2-150000.3.6.1 | 1.2-150000.3.6.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP3 | telnet | before 1.2-150000.3.6.1 | 1.2-150000.3.6.1 |
| SUSE:OpenStack Cloud 9 | krb5-appl | before 1.0.3-3.9.1 | 1.0.3-3.9.1 |
| SUSE:OpenStack Cloud 9 | telnet | before 1.2-167.10.1 | 1.2-167.10.1 |
Same product
gnu: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-24061telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER environment variable.KEV99Now
- CVE-2026-32746telnetd in GNU inetutils through 2.7 allows an out-of-bounds write in the LINEMODE SLC (Set Local Characters) suboption handler because add_40Plan
- CVE-2026-28372telnetd in GNU inetutils through 2.7 allows privilege escalation that can be exploited by abusing systemd service credentials support added 31Monitor
- CVE-2023-40303GNU inetutils before 2.5 may allow privilege escalation because of unchecked return values of set*id() family functions in ftpd, rcp, rlogin31Monitor
- CVE-2021-40491The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server ad26Monitor
- CVE-2026-32772telnet in GNU inetutils through 2.7 allows servers to read arbitrary environment variables from clients via NEW_ENVIRON SEND USERVAR.18Monitor
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:inetutils | 2:2.3-5 · Debian:12 | Package registry (OSV) |
| opensuse:telnet | 1.2-150000.3.6.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| suse:krb5-appl | 1.0.3-3.9.1 · SUSE:OpenStack Cloud 9 | Package registry (OSV) |
| suse:telnet | 1.2-150000.3.6.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP3 | Package registry (OSV) |
| suse:telnet | 1.2-167.10.1 · SUSE:OpenStack Cloud 9 | 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.
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
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-476 · NULL Pointer DereferenceCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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
- git.hadrons.org/cgit/debian/pkgs/inetutils.git/commit/?id=113da8021710d871c7dd72d2a4d5615d42d64289
- lists.debian.org/debian-lts-announce/2022/11/msg00033.html
- lists.gnu.org/archive/html/bug-inetutils/2022-08/msg00002.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.