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NVD / CVE Program· CNA GitHub_M

CVE-2022-21706: Multi-use invitations can grant access to other organizations in Zulip

Noroxi assessment

Priority: Monitor (action score 39/100)

  • 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: 1.2% (FIRST EPSS); higher than 68.1% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • No fixed version is recorded, but the references include a patch (commit or PR) link.
  • Severity is disputed: the assigning authority (CNA) scores it 7.2, NVD 9.8.

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

Zulip is an open-source team collaboration tool with topic-based threading. Zulip Server version 2.0.0 and above are vulnerable to insufficient access control with multi-use invitations. A Zulip Server deployment which hosts multiple organizations is vulnerable to an attack where an invitation created in one organization (potentially as a role with elevated permissions) can be used to join any other organization. This bypasses any restrictions on required domains on users' email addresses, may be used to gain access to organizations which are only accessible by invitation, and may be used to gain access with elevated privileges. This issue has been patched in release 4.10. There are no known workarounds for this issue. ### Patches _Has the problem been patched? What versions should users upgrade to?_ ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ ### References _Are there any links users can visit to find out more?_ ### For more information If you have any questions or comments about this advisory, you can discuss them on the [developer community Zulip server](https://zulip.com/developer-community/), or email the [Zulip security team](mailto:security@zulip.com).

CriticalCVSS 9.8 · v3.1—No exploit No fix recorded
Published
Feb 25, 2022
Updated
Jun 17, 2026
EPSS
1.2% · 68th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
9.8
CNA · GitHub_M
7.2
2.6 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.

Follow CVE-2022-21706

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
zulipzulip server

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • zulip zulip server2.0.0 and later · before 4.10.0

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.

  • zulip zulip

    • >= 2.0.0, < 4.10affected

Same product

zulip: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-18933In Zulip Server versions from 1.7.0 to before 2.0.7, a bug in the new user signup process meant that users who registered their account usin
    39Monitor
  • CVE-2020-15070Zulip Server 2.x before 2.1.7 allows eval injection if a privileged attacker were able to write directly to the postgres database, and chose
    35Monitor
  • CVE-2017-0910In Zulip Server before 1.7.1, on a server with multiple realms, a vulnerability in the invitation system lets an authorized user of one real
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2021-30479Apr 14, 2021 · An issue was discovered in Zulip Server before 3.4.
    21Monitor
  • ← EarlierCVE-2021-30487Apr 14, 2021 · In the topic moving API in Zulip Server 3.x before 3.4, organization administrators were able to move messages to streams in other organizat
    10Monitor
  • Later →CVE-2022-23656Mar 2, 2022 · Cross-site scripting vulnerability in Zulip Server
    21Monitor

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.

EPSS, last 120 days

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 researchers

Finders, 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

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-284 · Improper Access Control

CVSS vector

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

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.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records