CVE
BACnet Stack remote out-of-bounds read in readpropm client
Only the readpropm client application in bacnet-stack at commit e2bdbf6 and earlier is affected. Fixed in 1.4.5, 1.5.1, and 1.6.0.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Exploited
- Proof of concept public, per CISA
- Fix
- Fixed in 1.4.5, 1.5.1, 1.6.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 1.4.5, 1.5.1, 1.6.0.
- 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
- 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? →
- 43/100 · 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? →
- Unclear
- 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
- Exploitation: poc
- Automatable: yes
- Technical impact: partial
Summary
BACnet Stack, a BACnet open source protocol stack C library, has a flaw in its readpropm client application. A remote attacker, without logging in, can run a malicious BACnet/IP peer that replies to a legitimate ReadPropertyMultiple request with a malformed but structurally valid ACK, causing the client to read past the end of its global receive buffer and disrupt its availability.
Original description
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.5, 1.5.1, and 1.6.0, a remote out-of-bounds read exists in the official BACnet client application apps/readpropm in bacnet-stack commit e2bdbf6. When readpropm sends a legitimate ReadPropertyMultiple request to a malicious BACnet/IP peer, the peer can reply with a malformed but structurally valid ReadPropertyMultiple-ACK that drives the client into a global-buffer-overflow read on the global receive buffer Rx_Buf. This issue has been patched in versions 1.4.5, 1.5.1, and 1.6.0.
Who should check
Teams building or running the bacnet-stack readpropm BACnet client application at commit e2bdbf6 or versions up to 1.6.0-rc1.
“A remote out-of-bounds read exists in the official BACnet client application apps/readpropm”
cve.now Index
- Exploitation15/40CISA rates a proof of concept as public
- Exposure20/25No login or user action needed, CISA rates it automatable · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 73 if added to CISA KEV
- Would score about 68 if CISA's SSVC rates exploitation active
- Would score about 48 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 1.4.5, 1.5.1, 1.6.0.
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-2026-62973 (BACnet Stack: Remote Global-Buffer-Overflow Read in readpropm via Malformed ReadPropertyMultiple-ACK), 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-2026-62973 (entry last updated 2026-11-13):
Affected:
- bacnet-stack bacnet-stack: fixed in 1.4.5; fixed in 1.5.1; fixed in 1.6.0
Fixed versions: 1.4.5, 1.5.1, 1.6.0.
Conditions (all must be true for the bug to be hit):
- The client runs the readpropm application and sends a ReadPropertyMultiple request to a BACnet/IP peer. (source: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-3xxw-jfwm-rq9c)
- Affects the bacnet-stack readpropm client application at commit e2bdbf6 and earlier versions. (source: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-3xxw-jfwm-rq9c)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-62973 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-62973 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://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-3xxw-jfwm-rq9c
- https://github.com/bacnet-stack/bacnet-stack/pull/1395
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-2026-62973
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-62973"}.Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- bacnet-stack bacnet-stack
fixed in 1.4.5; fixed in 1.5.1; fixed in 1.6.0
Evidence 4
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 1
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-62973
Is CVE-2026-62973 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. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
When readpropm sends a ReadPropertyMultiple request to a malicious BACnet/IP peer, the peer can make the client read beyond the end of its receive buffer. This can crash the client, causing a denial of service.Source: github.com
Which versions are affected by CVE-2026-62973?
bacnet-stack: before 1.4.5; before 1.5.1; before 1.6.0.Source: cve.now feed data
Am I affected, and how do I check?
The readpropm client application at commit e2bdbf6 and earlier is affected. Check the bacnet-stack commit or version your readpropm build comes from to see whether it falls in that range.Source: github.com
How do I fix CVE-2026-62973?
Upgrade bacnet-stack to 1.4.5, 1.5.1, or 1.6.0, depending on which release line you use.Source: github.com