Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability
Roundcube · Webmail
The Roundcube Webmail product contains a persistent cross-site scripting flaw in its message handling, located in the rcube_string_replacer.php component of the library code, affecting versions before 1.4.14, 1.5.x before 1.5.4, and 1.6.x before 1.6.3. An unauthenticated remote attacker can send a text/plain e-mail containing crafted links that cause script to execute in the victim's browser when the user interacts with the message, such as by opening it.
Roundcube before 1.4.14, 1.5.x before 1.5.4, and 1.6.x before 1.6.3 allows XSS via text/plain e-mail messages with crafted links because of program/lib/Roundcube/rcube_string_replacer.php behavior.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 3/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 5 months after disclosure. Public exploit code (PoC-in-GitHub) appeared 5 days after disclosure.
- Disclosedday 0
- Public exploit codePoC-in-GitHub+5 days
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
3 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 3Initial AccessTA0001
This vulnerability is exploited by an adversary via malicious links embedded in trustworthy websites to infiltrate victim systems. Successful exploitation grants the adversary the ability to execute arbitrary code on the impacted system. The Russia-aligned hacking group TAG-70 has been attributed to exploiting this vulnerability. TAG-70 has used this vulnerability in an espionage campaign targeting European government and military agencies, as well as Iranian embassies in Russia, aiming to gather intelligence on European political and military activities. The campaign, active from early to mid-October 2023, is part of a broader pattern of Russian state-aligned cyber-espionage targeting email services.
ExecutionTA0002
DiscoveryTA0007
Detection
0 rules for this CVE · 131 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2023-43770 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Drive-by CompromiseT11893 general rules
Command and Scripting InterpreterT105995 general rules
- HackTool - Sliver C2 Implant Activity Patterncriticaltest
- Lazarus Group Activitycriticaltest
- REvil Kaseya Incident Malware Patternscriticaltest
- Turla Group Lateral Movementcriticaltest
- Windows Defender AMSI Trigger Detectedhighstable
- Windows Defender Threat Detectedhighstable
- Abusable DLL Potential Sideloading From Suspicious Locationhightest
- Add Insecure Download Source To Wingethightest
System Information DiscoveryT108233 general rules
- HackTool - PCHunter Executionhightest
- HackTool - winPEAS Executionhightest
- HackTool - WinPwn Executionhightest
- HackTool - WinPwn Execution - ScriptBlockhightest
- Network Reconnaissance Activityhightest
- Potential GobRAT File Discovery Via Grephightest
- Suspicious Kernel Dump Using Dtracehightest
- Bitbucket User Details Export Attempt Detectedmediumtest
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 30, 202629 Oct 2026
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- 44 more on OTX