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CVE-2026-78002

Rsyslog: rsyslog: denial of service via heap buffer overflow in rainerscript replace() function

No known exploitation. EPSS puts it in the 51st percentile. Only a workaround so far.

CVSS 3.17.5HighEPSS percentile51st0.7% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFixWorkaroundNo fixed build yet

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

No fixed build is published yet. The vendor describes a workaround.

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

A flaw was found in rsyslog. An unauthenticated remote attacker can trigger a heap buffer overflow in the RainerScript `replace()` function by sending specially crafted syslog messages. This vulnerability arises from an incorrect buffer size calculation during string replacement, causing memory corruption. Successful exploitation can lead to a denial of service (DoS) for the affected system.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS51st
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.7% chance of exploitation activity in the next 30 days, which ranks it in the 51st percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

26 events over 29 days, from the signal feeds we watch.

  1. Workaround availablerecord updated
  2. Workaround availableworkaround available, record updated, record updated
  3. Workaround availablerecord updated
  4. Workaround availableworkaround available, record updated, record updated
  5. OpenVAS check added
  6. Workaround availablerecord updated

Affected products

And 4 more affected products. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

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

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 4 more references. See all after sign-in

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