SMTP Command Injection in iCalendar Attachments to emails via newlines in Nextcloud Server
Noroxi assessment
Priority: Monitor (action score 15/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 2.5% (FIRST EPSS); higher than 84.5% of all records.
- Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. A user must open a link or visit a page. No special conditions are required; it is repeatable.
- No fixed version is recorded, but the references include a patch (commit or PR) link.
Low priority for now. See the fix and affected versions sections below.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Nextcloud server is an open source personal cloud server. Affected versions were found to be vulnerable to SMTP command injection. The impact varies based on which commands are supported by the backend SMTP server. However, the main risk here is that the attacker can then hijack an already-authenticated SMTP session and run arbitrary SMTP commands as the email user, such as sending emails to other users, changing the FROM user, and so on. As before, this depends on the configuration of the server itself, but newlines should be sanitized to mitigate such arbitrary SMTP command injection. It is recommended that the Nextcloud Server is upgraded to 22.2.8 , 23.0.5 or 24.0.1. There are no known workarounds for this issue.
- Published
- Jul 5, 2022
- Updated
- Jun 17, 2026
- EPSS
- 2.5% · 84th percentile
- CWE
- CWE-74
Report tools
Action score
15
Monitor
Low priority for now.
- CVSS
- 14 / 40 · 3.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.5%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 3.5
- CNA · GitHub_M
- 5.4
- 1.9 point gap
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| nextcloud | nextcloud server | cpe:2.3:a:nextcloud:nextcloud_server |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- nextcloud nextcloud serverbefore 19.0.13.7
- nextcloud nextcloud serverbefore 22.2.8
- nextcloud nextcloud server20.0.0 and later · before 20.0.14.6
- nextcloud nextcloud server21.0.0 and later · before 21.0.9.5
- nextcloud nextcloud server23.0.0 and later · before 23.0.5
- nextcloud nextcloud server24.0.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
nextcloud security-advisories
- < 22.2.8, >= 23.0.0, < 23.0.5, >= 24.0.0, < 24.0.1affected
Same product
nextcloud: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-26482Scope of workflow operations is not validated in nextcloud server40Plan
- CVE-2021-32802Preview generation used third-party library not suited for user-generated content in Nextcloud server40Plan
- CVE-2021-32726Webauthn tokens not removed after user has been deleted40Plan
Published before and after this one in the same product
- ← EarlierCVE-2022-29163May 20, 2022 · Bypass of password requirements when sharing a folder via the Circles app in Nextcloud Server17Monitor
- ← EarlierCVE-2022-29243May 31, 2022 · Improper input-size validation on the user new session name in Nextcloud Server17Monitor
- Later →CVE-2022-31118Aug 4, 2022 · Missing brute force protection on cloud federation sharing in Nextcloud Server21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- low · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- Low
- Availability impact
- None
Weakness class (CWE)
CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- HTTP Request SplittingCAPEC-105likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- Format String InjectionCAPEC-135likelihood: High · High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.