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CVE-2026-72529

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in TrueConf Server. For every flaw being used in attacks, see Exploited flaws; for TrueConf’s, see TrueConf flaws being used in attacks.

CVE-2026-72529 is a security flaw in TrueConf Server. Attackers can get into TrueConf Server without a valid password. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 20 Aug 2026.[1]

TrueConf Server is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 5.3, 5.3.9, 5.4.9 and 5.5.5 of TrueConf Server.

Description

CISA calls it a missing authentication for critical function in TrueConf Server. In its words: “TrueConf Server contains a missing authentication for critical function vulnerability which could allow a remote unauthorized attacker with network access via port 4307/TCP to execute an arbitrary script.”[1]

The underlying weakness is missing authentication (CWE-306), in MITRE’s list of common software weaknesses.[2]

It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by the organisation that published the CVE using CVSS 3.1.[2]

Affected versions

NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]

ProductFixed in
TrueConf Server5.3
TrueConf Server5.3.9
TrueConf Server5.4.9
TrueConf Server5.5.5

Most families won’t have TrueConf Server; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 20 Aug 2026, within a day of it being made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 23 Aug 2026 to fix it.[1]

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 1%. That’s in the top 27% of the flaws it scores.[4]

CISA assesses it as automatable: attackers can run it against many targets at once.

CISA doesn’t say who was attacked, or how.

Fix

TrueConf has published a fix or advice.[3] CISA’s required action: “Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes).”[1]

  1. Check whether you use it.TrueConf Server is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
  2. Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 5.3, 5.3.9, 5.4.9 and 5.5.5 of TrueConf Server), or not in use. CISA gave US government agencies until 23 Aug 2026 to fix it.
  3. If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.

You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2]
CISA adds it to its catalog of flaws known to be used in attacks.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 1%.[4]

See also

Other TrueConf Server flaws

Other TrueConf flaws

  • CVE-2026-3502, TrueConf Client: download of code without integrity check ·

Other missing authentication flaws

  • CVE-2026-111357, Ivanti Connect Secure: missing authentication for critical function ·
  • CVE-2026-67277, MikroTik RouterOS: missing authentication for critical function ·
  • CVE-2026-81578, PaperCut NG/MF: missing authentication for critical function ·
  • CVE-2026-56164, Microsoft SharePoint Server: missing authentication for critical function ·
  • CVE-2026-20253, Splunk Enterprise: missing authentication for critical function ·

Added the same day

Every TrueConf flaw on CISA’s list · Everything added in August 2026

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “TrueConf Server Missing Authentication for Critical Function Vulnerability”. Known Exploited Vulnerabilities Catalog, added 20 Aug 2026.
  2. ^ National Institute of Standards and Technology. “CVE-2026-72529 Detail”. National Vulnerability Database, published 19 Aug 2026.
  3. ^ TrueConf. Advisories and fixes: trueconf.com, ics-cert.kaspersky.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.015, percentile 73.7, 31 Oct 2026.
  5. CVE Program. “CVE-2026-72529”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.