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Fencer Vulns
high 7.5

CVE-2020-28924 json

Use of Cryptographically Weak Pseudo-Random Number Generator in Rclone

published 2020-11-19 5 y ago modified 2026-09-08 2 mo ago also BIT-rclone-2020-28924 , EUVD-2021-1401 , GHSA-rmw5-xpg9-jr29 , GO-2022-0878 , JLSEC-2026-278

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

An issue was discovered in Rclone before 1.53.3. Due to the use of a weak random number generator, the password generator has been producing weak passwords with much less entropy than advertised. The suggested passwords depend deterministically on the time the second rclone was started. This limits the entropy of the passwords enormously. These passwords are often used in the crypt backend for encryption of data. It would be possible to make a dictionary of all possible passwords with about 38 million entries per password length. This would make decryption of secret material possible with a plausible amount of effort. NOTE: all passwords generated by affected versions should be changed.

Patch / fix

  • go github.com/rclone/rclone 1.53.3
  • bitnami rclone 1.53.3
  • julia Rclone_jll 1.55.1+0
  • rclone rclone 1.53.3
  • rclone Debian 13, Debian 12 1.53.3-1

debian advisories DEBIAN-CVE-2020-28924

  • rclone openSUSE Tumbleweed 1.55.1-1.3
  • rclone Package Hub 15 SP2 1.53.3-bp152.2.4.11
  • rclone Package Hub 15 SP1 1.53.3-bp151.4.6.1
  • rclone openSUSE Leap 15.1 1.53.3-lp151.3.6.1
  • rclone openSUSE Leap 15.2 1.53.3-lp152.2.3.1

opensuse advisories openSUSE-SU-2024:11297-1openSUSE-SU-2021:0272-1openSUSE-SU-2020:2168-1openSUSE-SU-2020:2035-1openSUSE-SU-2020:2008-1

  • rclone Arch Linux 1.53.3-1

arch linux advisories AVG-1286

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-28924 updated

rclone: Insecure passwords generated by rclone config (security hardening)

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.38% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/rclone/rclone/issues/4783 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/rclone/rclone
<1.53.3
1.53.3
bitnami rclone
<1.53.3
1.53.3
julia Rclone_jll
<1.55.1+0
1.55.1+0

Classification

Weakness
  • CWE-331 Insufficient Entropy
  • CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

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.