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Fencer Vulns
high 8.1

CVE-2021-43963 json

An issue was discovered in Couchbase Sync Gateway 2.7.0 through 2.8.2.

published 2021-12-07 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-30825

cvss
8.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

An issue was discovered in Couchbase Sync Gateway 2.7.0 through 2.8.2. The bucket credentials used to read and write data in Couchbase Server were insecurely being stored in the metadata within sync documents written to the bucket. Users with read access could use these credentials to obtain write access. (This issue does not affect clusters where Sync Gateway is authenticated with X.509 client certificates. This issue also does not affect clusters where shared bucket access is not enabled on Sync Gateway.)

Patch / fix

  • couchbase sync_gateway 2.8.3

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 5.5 AV:N/AC:L/Au:S/C:P/I:P/A:N

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.