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Fencer Vulns
high 7.1

CVE-2021-3889 json

Use of Out-of-range Pointer Offset in bfabiszewski/libmobi

published 2021-10-19 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27121

cvss
7.1
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

libmobi is vulnerable to Use of Out-of-range Pointer Offset

Patch / fix

  • bfabiszewski bfabiszewski/libmobi 0.8

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-2021-3889 updated cvss 7.1

libmobi: out-of-bounds read due to incomplete check in mobi_decompress_huffman_internal() in src/compression.c

  • 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

1.29% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.dev https://huntr.dev/bounties/efb3e261-3f7d-4a45-8114-e0ace6b21516 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 7.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:N/A:P

Affected products

  • bfabiszewski bfabiszewski/libmobi

Classification

Weakness
  • CWE-823 Use of Out-of-range Pointer Offset
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

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.