The Node.js web service on VOS (previously Versa FlexVNF) is used for URL-based Zero Touch Provisioning (ZTP) of the VOS appliance and is…
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Specific setups only
Do first: Workaround: Disable the Node.js web service on the VOS.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.29% · 22nd percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 21/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Node.js web service on VOS (formerly Versa FlexVNF), which is used for URL-based Zero Touch Provisioning and is not needed after setup, contains a hardcoded session-signing secret shared by all VOS appliances. An attacker who can reach the service over the network, needs high privileges, and requires user interaction could forge session cookies that every VOS appliance in the deployment accepts, which can fully compromise confidentiality, integrity, and availability. The flaw does not affect devices where this web service has been disabled.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
The Node.js web service on VOS (previously Versa FlexVNF) is used for URL-based Zero Touch Provisioning (ZTP) of the VOS appliance and is not required after provisioning is complete. The express-session middleware in server.js is configured with a hardcoded secret that is identical across all VOS appliances and is used to sign session cookies. An attacker who obtains a valid session ID from any source can compute the correct HMAC-SHA256 signature and forge a session cookie that the server accepts as legitimate. Because the secret is shared across all VOS appliances, a forged cookie is accepted by any VOS appliance in the deployment.
Versa’s security hardening guide for Hubs, Branches, and Controllers recommends disabling the Node.js web service after the initial provisioning of the VOS device. This vulnerability is not exploitable on VOS devices where the Node.js web service has been disabled.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure8/25Specific setups only, reachable over the network
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.6/10CVSS 7.6
- No patch5/5No patch listed yet
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
- Would score about 28 if CISA's SSVC rates it automatable
What to do
Workaround: Disable the Node.js web service on the VOS.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-107243 (The Node.js web service on VOS (previously Versa FlexVNF) is used for URL-based Zero Touch Provisioning (ZTP) of the VOS appliance and is…), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-107243 (entry last updated 2026-11-10): Affected: - Versa VOS: from 21.1.1, through 21.2.3 Fixed versions: none listed yet. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: network access, high-privilege login, a user action. Workaround: Disable the Node.js web service on the VOS. (source: https://www.cve.org/CVERecord?id=CVE-2026-107243) CISA KEV: CVE-2026-107243 is not listed as of cve.now's last read. This KEV status is for CVE-2026-107243 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://security-portal.versa-networks.com/emailbulletins/6af22ae2dd1c93ddc0a3e838 - https://www.cve.org/CVERecord?id=CVE-2026-107243 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-107243 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-107243.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Versa VOS
From 21.1.1 · through 21.2.3
Evidence 3
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 1
- Link
Corrections
None so far.
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Questions about CVE-2026-107243
Is CVE-2026-107243 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-107243?
VOS: from 21.1.1 through 21.2.3.Source: cve.now feed data
How do I fix CVE-2026-107243?
The checked facts list no fixed version, so no upgrade target is given. The vendor's mitigation is to disable the Node.js web service on the VOS.Source: cve.org
What if there's no patch?
Disable the Node.js web service on the VOS, as the vendor's mitigation says. That service is used for URL-based ZTP, so provisioning that relies on it will be affected until a fix is available.Source: cve.org