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CVE-2022-25219· NVD / CVE Program· CNA tenable

A null byte interaction error has been discovered in the code that the telnetd_startup daemon uses to construct a pair of ephemeral password

A null byte interaction error has been discovered in the code that the telnetd_startup daemon uses to construct a pair of ephemeral passwords that allow a user to spawn a telnet service on the router, and to ensure that the telnet service persists upon reboot. By means of a crafted exchange of UDP packets, an unauthenticated attacker on the local network can leverage this null byte interaction error in such a way as to make those ephemeral passwords predictable (with 1-in-94 odds). Since the attacker must manipulate data processed by the OpenSSL function RSA_public_decrypt(), successful exploitation of this vulnerability depends on the use of an unpadded RSA cipher (CVE-2022-25218).

HighCVSS 8.4 · v3.1—No exploit No fix recorded
Published
Mar 10, 2022
Updated
Jun 17, 2026
EPSS
0.8% · 54th percentile
CWE
—
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Action score

33

Monitor

Low priority for now.

CVSS
33 / 40 · 8.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

Affected systems

VendorProduct
phicommk2 firmware
phicommk2
phicommk3 firmware
phicommk3
phicommk3c firmware
phicommk3c
phicommk2g firmware
phicommk2g
phicommk2p firmware
phicommk2p

Affected versions

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

  • phicomm k2 firmwareup to 22.5.9.163 inclusive
  • phicomm k2g firmwareup to 22.6.3.20 inclusive
  • phicomm k2p firmwareup to 20.4.1.7 inclusive
  • phicomm k3 firmwareup to 21.5.37.246 inclusive
  • phicomm k3c firmwareup to 32.1.15.93 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (tenable). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a Phicomm Routers

    • K3 >= 21.5.37.246, K3C >= 32.1.22.113, K2P >= 20.4.1.7, K2 A7 >= 22.6.506.28, K2G A1 >= 22.6.3.20affected

Same product

phicomm: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-25218The use of the RSA algorithm without OAEP, or any other padding scheme, in telnetd_startup, allows an unauthenticated attacker on the local
    32Monitor
  • CVE-2023-40796Phicomm k2 v22.6.529.216 was discovered to contain a command injection vulnerability via the function luci.sys.call.
    31Monitor
  • CVE-2022-48072Phicomm K2G v22.6.3.20 was discovered to contain a command injection vulnerability via the autoUpTime parameter in the automatic upgrade fun
    31Monitor
  • CVE-2022-48070Phicomm K2 v22.6.534.263 was discovered to contain a command injection vulnerability via the autoUpTime parameter in the automatic upgrade f
    31Monitor
  • CVE-2022-25217Use of a hard-coded cryptographic key pair by the telnetd_startup service allows an attacker on the local area network to obtain a root shel
    31Monitor
  • CVE-2022-48073Phicomm K2G v22.6.3.20 was discovered to store the root and admin passwords in plaintext.
    30Monitor

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

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.

EPSS, last 120 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.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system 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
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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.

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Change log

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

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