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Fencer Intel
medium 4.7

CVE-2018-20482 json

GNU Tar through 1.30, when --sparse is used, mishandles file shrinkage during read access, which allows local users to cause a denial of se…

published 2018-12-26 7 y ago modified 2026-10-14 26 d ago also EUVD-2018-13036

cvss
4.7
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 45%
public exploits
0
none known

Summary

GNU Tar through 1.30, when --sparse is used, mishandles file shrinkage during read access, which allows local users to cause a denial of service (infinite read loop in sparse_dump_region in sparse.c) by modifying a file that is supposed to be archived by a different user's process (e.g., a system backup running as root).

Patch / fix

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • tar Debian 14, Debian 13, Debian 12 1.30+dfsg-3.1

debian advisories DEBIAN-CVE-2018-20482

  • tar Ubuntu 16.04 LTS 1.28-2.1ubuntu0.2
  • tar Ubuntu 18.04 LTS 1.29b-2ubuntu0.2
  • tar Ubuntu Pro 14.04 LTS 1.27.1-1ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2018-20482

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tar SLE Real Time 15 SP2, SLE Module for Basesystem 15 SP3, SLE Micro 5.2 +3 more 1.34-150000.3.12.1
  • tar SLES for SAP 12 SP5, SLES 12 SP5 1.27.1-15.6.3
  • tar SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 1.27.1-14.8.1
  • tar SLE Module for Basesystem 15 1.30-3.3.2

suse advisories SUSE-SU-2022:1548-1SUSE-SU-2020:2806-1SUSE-SU-2019:14215-1SUSE-SU-2019:0926-1

  • tar openSUSE Tumbleweed 1.34-2.2
  • tar openSUSE Leap 15.0 1.30-lp150.7.1

opensuse advisories openSUSE-SU-2024:11422-1openSUSE-SU-2019:1237-1

  • tar Alpine 3.24, Alpine 3.23, Alpine 3.22 +16 more 1.31-r0

alpine advisories ALPINE-CVE-2018-20482

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tar Arch Linux 1.31-1

arch linux advisories AVG-841

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-2018-20482 updated cvss 5.5

tar: Infinite read loop in sparse_dump_region function in sparse.c

  • Red Hat Enterprise Linux 5 tar Red Hat Enterprise Linux 6 tar Red Hat Enterprise Linux 7 tar
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 8 tar
    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

cisa ICSA-23-348-10 updated cvss 4.7

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • news.ycombinator.com https://news.ycombinator.com/item?id=18745431 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 4.7 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 1.9 AV:L/AC:M/Au:N/C:N/I:N/A:P

Affected products

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Intel 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.