Versalink Firmware: Loop with Unreachable Exit Condition
CVE-2022-23968 is a high-severity loop with unreachable exit condition vulnerability in Versalink Firmware from Xerox, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Versalink Firmware versions: 42.01 and earlier; 50.00 through 50.61. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.91% chance of exploitation within 30 days, higher than 80% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Versalink Firmware you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Xerox | Versalink Firmware | 42.01 and earlier; 50.00 through 50.61 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 7.8 | High | NVD |
Official description
Xerox VersaLink devices on specific versions of firmware before 2022-01-26 allow remote attackers to brick the device via a crafted TIFF file in an unauthenticated HTTP POST request. There is a permanent denial of service because image parsing causes a reboot, but image parsing is restarted as soon as the boot process finishes. However, this boot loop can be resolved by a field technician. The TIFF file must have an incomplete Image Directory. Affected firmware versions include xx.42.01 and xx.50.61. NOTE: the 2022-01-24 NeoSmart article included "believed to affect all previous and later versions as of the date of this posting" but a 2022-01-26 vendor statement reports "the latest versions of firmware are not vulnerable to this issue."
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Loop with Unreachable Exit Condition
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
More Loop with Unreachable Exit Condition vulnerabilities (CWE-835)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- twitter.com/mqudsi/status/1485756915187695618Third Party Advisory
Technical write-ups (may include proof of concept)
- neosmart.net/blog/2022/xerox-vulnerability-allows-unauthenticated-network-users-to-remotely-brick-printers/Exploit, Third Party Advisory
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