CVE-2018-20482

Exp

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).

Published: 2018-12-26 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-20482 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.02%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2018-20482

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2018-20482

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.06% 0.02% -0.04%
2 2025-11-18 0.04% 0.06% +0.02%
3 2023-03-07 — 0.04% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-20482

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.7 3.1 MEDIUM
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.0 3.6 [email protected]
1.9 2.0 LOW
AV:L/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.4 2.9 [email protected]

Weakness enumeration for CVE-2018-20482

OS Trackers for CVE-2018-20482

vendor priority summary link
alpine medium CVE-2018-20482: 1 source package rows (tar); 15 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 5. https://security.alpinelinux.org/vuln/CVE-2018-20482
debian not yet assigned CVE-2018-20482 not yet assigned priority: Debian including 1 source packages (tar), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-20482
gentoo normal CVE-2018-20482: 1 GLSA(s) (201903-05), 1 atom(s) (app-arch/tar); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-20482
redhat low — https://access.redhat.com/security/cve/CVE-2018-20482
suse low CVE-2018-20482 severity low: SUSE including 317 source package names (0.23.1-12.3:tar-1.34-150000.3.12.1, 0.45.0.7.7.1:tar-1.30-3.3.2, …), 693 product×package rows across 405 product lines (Container bci/bci-sle15-kernel-module-devel, Container bci/kiwi, … (405 product lines)): Fixed 542, Known Affected 151. https://www.suse.com/security/cve/CVE-2018-20482/
ubuntu low CVE-2018-20482 low priority: Ubuntu including 1 source packages (tar), 9 status rows across 9 suites (bionic, cosmic, disco, eoan, focal, groovy, trusty, upstream, xenial): not-affected 4, released 4, ignored 1. https://ubuntu.com/security/CVE-2018-20482

Affected software / configurations for CVE-2018-20482

Vendor Product Version Raw CPE
gnu tar <= 1.30 cpe:2.3:a:gnu:tar:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
opensuse leap 15.0 cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*

References for CVE-2018-20482

URL Tags
http://git.savannah.gnu.org/cgit/tar.git/commit/?id=c15c42ccd1e2377945fd0414eca1a49294bff454 Patch Third Party Advisory
http://lists.gnu.org/archive/html/bug-tar/2018-12/msg00023.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00077.html Mailing List Third Party Advisory
http://www.securityfocus.com/bid/106354 Third Party Advisory VDB Entry
https://lists.debian.org/debian-lts-announce/2018/12/msg00023.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/11/msg00025.html Mailing List Third Party Advisory
https://news.ycombinator.com/item?id=18745431 Exploit Third Party Advisory
https://security.gentoo.org/glsa/201903-05 Third Party Advisory
https://twitter.com/thatcks/status/1076166645708668928 Patch Third Party Advisory
https://utcc.utoronto.ca/~cks/space/blog/sysadmin/TarFindingTruncateBug Patch Third Party Advisory
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