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CVE-2018-20482

GNU Tar through 1.30, when --sparse is used, mishandles file shrinkage during read access, which...

4.7 MediumFix available

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).

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
High
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.53%Down 0.8 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 4.7

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).

Record
CVE-2018-20482
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
1.9 LowAV:L/AC:M/Au:N/C:N/I:N/A:P
Weakness
CWE-835
Updated
2026-11-02
CVE List No score

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).

Record
CVE-2018-20482
Updated
2026-11-02
EUVDEUVD-2018-13036 No score

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).

Record
EUVD-2018-13036
Updated
2026-11-02
GitHub AdvisoriesGHSA-pm5x-48pq-67cq 4.7

GNU Tar through 1.30, when --sparse is used, mishandles file shrinkage during read access, which...

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).

Record
GHSA-pm5x-48pq-67cq
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-835
Updated
2026-11-02
OSVALPINE-CVE-2018-20482 4.7

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).

Record
ALPINE-CVE-2018-20482
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVBELL-CVE-2018-20482 4.7

CVE-2018-20482 does not affect BellSoft software

Record
BELL-CVE-2018-20482
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 11 moreShow less
OSV 4.7

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).

Record
CVE-2018-20482
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-03
OSVDEBIAN-CVE-2018-20482 4.7

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).

Record
DEBIAN-CVE-2018-20482
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2018-20482 4.7

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).

Record
UBUNTU-CVE-2018-20482
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 3.0
4.7 MediumCVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVMGASA-2019-0034 No score

GNU tar has been updated to fix CVE-2018-20482

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).

Record
MGASA-2019-0034
Updated
2026-11-02
OSVopenSUSE-SU-2019:1237-1 No score

Security update for tar

This update for tar fixes the following issues:

Security issues fixed:

  • CVE-2019-9923: Fixed a denial of service while parsing certain archives with malformed extended headers in pax_decode_header() (bsc#1130496).
  • CVE-2018-20482: Fixed a denial of service when the '--sparse' option mishandles file shrinkage during read access (bsc#1120610).

This update was imported from the SUSE:SLE-15:Update update project.

Record
openSUSE-SU-2019:1237-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:11422-1 No score

tar-1.34-2.2 on GA media

These are all security issues fixed in the tar-1.34-2.2 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:11422-1
Updated
2026-11-02
OSVSUSE-SU-2019:0926-1 No score

Security update for tar

This update for tar fixes the following issues:

Security issues fixed:

  • CVE-2019-9923: Fixed a denial of service while parsing certain archives with malformed extended headers in pax_decode_header() (bsc#1130496).
  • CVE-2018-20482: Fixed a denial of service when the '--sparse' option mishandles file shrinkage during read access (bsc#1120610).
Record
SUSE-SU-2019:0926-1
Updated
2026-11-02
OSVSUSE-SU-2019:14215-1 No score

Security update for tar

This update for tar to version 1.27.1 fixes the following issues:

tar 1.27.1 brings following changes (jsc#ECO-339)

  • Sparse files with large data
  • No backticks in quoting
  • --owner and --group names and numbers
  • Support for POSIX ACLs, extended attributes and SELinux context.
  • Passing command line arguments to external commands.
  • New configure option --enable-gcc-warnings, intended for debugging.
  • New warning control option --warning=[no-]record-size
  • New command line option --keep-directory-symlink
  • Fix unquoting of file names obtained via the -T option.
  • Fix GNU long link header timestamp (backward compatibility).

Security issues fixed:

  • CVE-2019-9923: Fixed a denial of service while parsing certain archives with malformed extended headers in pax_decode_header() (bsc#1130496).
  • CVE-2018-20482: Fixed a denial of service when the '--sparse' option mishandles file shrinkage during read access (bsc#1120610).
Record
SUSE-SU-2019:14215-1
Updated
2026-11-02
OSVSUSE-SU-2020:2806-1 No score

Security update for tar

This update for tar fixes the following issues:

Security issues fixed:

  • CVE-2019-9923: Fixed a denial of service while parsing certain archives with malformed extended headers in pax_decode_header() (bsc#1130496).
  • CVE-2018-20482: Fixed a denial of service when the '--sparse' option mishandles file shrinkage during read access (bsc#1120610).
Record
SUSE-SU-2020:2806-1
Updated
2026-11-02
OSVSUSE-SU-2022:1548-1 No score

Security update for tar

This update for tar fixes the following issues:

  • CVE-2021-20193: Fixed a memory leak in read_header() in list.c (bsc#1181131).

  • CVE-2019-9923: Fixed a null-pointer dereference in pax_decode_header in sparse.c (bsc#1130496).

  • CVE-2018-20482: Fixed infinite read loop in sparse_dump_region in sparse.c (bsc#1120610).

  • Update to GNU tar 1.34:

    • Fix extraction over pipe
    • Fix memory leak in read_header (CVE-2021-20193) (bsc#1181131)
    • Fix extraction when . and .. are unreadable
    • Gracefully handle duplicate symlinks when extracting
    • Re-initialize supplementary groups when switching to user privileges
  • Update to GNU tar 1.33:

    • POSIX extended format headers do not include PID by default
    • --delay-directory-restore works for archives with reversed member ordering
    • Fix extraction of a symbolic link hardlinked to another symbolic link
    • Wildcards in exclude-vcs-ignore mode don't match slash
    • Fix the --no-overwrite-dir option
    • Fix handling of chained renames in incremental backups
    • Link counting works for file names supplied with -T
    • Accept only position-sensitive (file-selection) options in file list files
  • prepare usrmerge (bsc#1029961)

  • Update to GNU 1.32

    • Fix the use of --checkpoint without explicit --checkpoint-action
    • Fix extraction with the -U option
    • Fix iconv usage on BSD-based systems
    • Fix possible NULL dereference (savannah bug #55369) [bsc#1130496] [CVE-2019-9923]
    • Improve the testsuite
  • Update to GNU 1.31

    • Fix heap-buffer-overrun with --one-top-level, bug introduced with the addition of that option in 1.28
    • Support for zstd compression
    • New option '--zstd' instructs tar to use zstd as compression program. When listing, extractng and comparing, zstd compressed archives are recognized automatically. When '-a' option is in effect, zstd compression is selected if the destination archive name ends in '.zst' or '.tzst'.
    • The -K option interacts properly with member names given in the command line. Names of members to extract can be specified along with the '-K NAME' option. In this case, tar will extract NAME and those of named members that appear in the archive after it, which is consistent with the semantics of the option. Previous versions of tar extracted NAME, those of named members that appeared before it, and everything after it.
    • Fix CVE-2018-20482 - When creating archives with the --sparse option, previous versions of tar would loop endlessly if a sparse file had been truncated while being archived.
Record
SUSE-SU-2022:1548-1
Updated
2026-11-02
OSVUSN-4692-1 No score

tar vulnerabilities

Chris Siebenmann discovered that tar incorrectly handled extracting files resized during extraction when invoked with the --sparse flag. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 12.04 ESM, Ubuntu 14.04 ESM, Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-20482)

Daniel Axtens discovered that tar incorrectly handled certain malformed tar files. If a user or automated system were tricked into processing a specially crafted tar archive, a remote attacker could use this issue to cause tar to crash, resulting in a denial of service. (CVE-2019-9923)

Record
USN-4692-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
tar
Alpine:v3.10
before 1.31-r0
1.31-r0
tar
Alpine:v3.11
before 1.31-r0
1.31-r0
tar
Alpine:v3.12
before 1.31-r0
1.31-r0
tar
Alpine:v3.13
before 1.31-r0
1.31-r0
tar
Alpine:v3.14
before 1.31-r0
1.31-r0
tar
Alpine:v3.15
before 1.31-r0
1.31-r0
tar
Alpine:v3.16
before 1.31-r0
1.31-r0
tar
Alpine:v3.17
before 1.31-r0
1.31-r0
tar
Alpine:v3.18
before 1.31-r0
1.31-r0
tar
Alpine:v3.19
before 1.31-r0
1.31-r0
Show 32 moreShow less
Affected packages
PackageAffectedFixed
tar
Alpine:v3.20
before 1.31-r0
1.31-r0
tar
Alpine:v3.21
before 1.31-r0
1.31-r0
tar
Alpine:v3.22
before 1.31-r0
1.31-r0
tar
Alpine:v3.23
before 1.31-r0
1.31-r0
tar
Alpine:v3.24
before 1.31-r0
1.31-r0
tar
Alpine:v3.6
before 1.31-r0
1.31-r0
tar
Alpine:v3.7
before 1.31-r0
1.31-r0
tar
Alpine:v3.8
before 1.31-r0
1.31-r0
tar
Alpine:v3.9
before 1.31-r0
1.31-r0
tar
Debian:12
before 1.30+dfsg-3.1
1.30+dfsg-3.1
tar
Debian:13
before 1.30+dfsg-3.1
1.30+dfsg-3.1
tar
Debian:14
before 1.30+dfsg-3.1
1.30+dfsg-3.1
tar
Debian:8
before 1.27.1-2+deb8u2, plus listed versions
1.27.1-21.27.1-2+deb8u1
1.27.1-2+deb8u2
tar
Debian:9
before 1.29b-1.1+deb9u1, plus listed versions
1.29b-1.1
1.29b-1.1+deb9u1
tar
Mageia:6
before 1.31-1.mga6
1.31-1.mga6
tar
SUSE:Linux Enterprise Module for Basesystem 15
before 1.30-3.3.2
1.30-3.3.2
tar
SUSE:Linux Enterprise Point of Sale 11 SP3
before 1.27.1-14.8.1
1.27.1-14.8.1
tar
SUSE:Linux Enterprise Server 11 SP4-LTSS
before 1.27.1-14.8.1
1.27.1-14.8.1
tar
SUSE:Linux Enterprise Server 12 SP5
before 1.27.1-15.6.3
1.27.1-15.6.3
tar
SUSE:Linux Enterprise Server for SAP Applications 12 SP5
before 1.27.1-15.6.3
1.27.1-15.6.3
tar
SUSE:Linux Enterprise Module for Basesystem 15 SP3
before 1.34-150000.3.12.1
1.34-150000.3.12.1
tar
SUSE:Linux Enterprise Real Time 15 SP2
before 1.34-150000.3.12.1
1.34-150000.3.12.1
tar
SUSE:Linux Enterprise Micro 5.0
before 1.34-150000.3.12.1
1.34-150000.3.12.1
tar
SUSE:Linux Enterprise Micro 5.1
before 1.34-150000.3.12.1
1.34-150000.3.12.1
tar
SUSE:Linux Enterprise Micro 5.2
before 1.34-150000.3.12.1
1.34-150000.3.12.1
tar
openSUSE:Leap 15.3
before 1.34-150000.3.12.1
1.34-150000.3.12.1
tar
Ubuntu:Pro:14.04:LTS
before 1.27.1-1ubuntu0.1+esm1, plus listed versions
1.26+dfsg-81.27-31.27-41.27.1-11.27.1-1ubuntu0.1
1.27.1-1ubuntu0.1+esm1
tar
Ubuntu:16.04:LTS
before 1.28-2.1ubuntu0.2, plus listed versions
1.27.1-21.28-2ubuntu11.28-2.11.28-2.1ubuntu0.1
1.28-2.1ubuntu0.2
tar
Ubuntu:18.04:LTS
before 1.29b-2ubuntu0.2, plus listed versions
1.29b-21.29b-2ubuntu0.1
1.29b-2ubuntu0.2
tar
Ubuntu:20.04:LTS
before 1.30+dfsg-7ubuntu0.20.04.1, plus listed versions
1.30+dfsg-61.30+dfsg-7
1.30+dfsg-7ubuntu0.20.04.1
tar
openSUSE:Leap 15.0
before 1.30-lp150.7.1
1.30-lp150.7.1
tar
openSUSE:Tumbleweed
before 1.34-2.2
1.34-2.2

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-20482 is a medium vulnerability (CVSS 4.7) in Gnu Tar, published December 26, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.53%, the 45th percentile. Fixed in tar 1.31-r0.

References

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