CVE-2018-20783

Exp

In PHP before 5.6.39, 7.x before 7.0.33, 7.1.x before 7.1.25, and 7.2.x before 7.2.13, a buffer over-read in PHAR reading functions may allow an attacker to read allocated or unallocated memory past the actual data when trying to parse a .phar file. This is related to phar_parse_pharfile in ext/phar/phar.c.

Published: 2019-02-21 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-20783 is rated High Exploit Risk (77.7/100): CVSS High severity, with high exploitation likelihood (EPSS 5.66%, 92th percentile). 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-2018-20783

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

Exploit prediction scoring system (EPSS) score for CVE-2018-20783

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 2026-06-15 5.10% 5.66% +0.56%
2 2026-04-13 6.54% 5.10% -1.43%
3 2026-03-04 — 6.54% —

Full EPSS history (47 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-20783

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2018-20783

OS Trackers for CVE-2018-20783

vendor priority summary link
alpine high CVE-2018-20783: 1 source package rows (php7); 1 state rows across 1 repos (edge-community); fixed 1, open 0. https://security.alpinelinux.org/vuln/CVE-2018-20783
redhat low — https://access.redhat.com/security/cve/CVE-2018-20783
suse medium CVE-2018-20783 severity moderate: SUSE including 912 source package names (apache2-mod_php5-5.5.14-109.51.6, apache2-mod_php53-5.3.17-112.58.1, …), 1898 product×package rows across 54 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (54 product lines)): Fixed 1543, Known Not Affected 355. https://www.suse.com/security/cve/CVE-2018-20783/
ubuntu low CVE-2018-20783 low priority: Ubuntu including 4 source packages (php5, php7.0, php7.2, php7.3), 24 status rows across 6 suites (bionic, cosmic, disco, trusty, upstream, xenial): DNE 15, released 9. https://ubuntu.com/security/CVE-2018-20783

Affected software / configurations for CVE-2018-20783

Vendor Product Version Raw CPE
php php < 5.6.39 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
php php >= 7.0.0, < 7.0.33 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
php php >= 7.1.0, < 7.1.25 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
php php >= 7.2.0, < 7.2.13 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
opensuse leap 42.3 cpe:2.3:o:opensuse:leap:42.3:*:*:*:*:*:*:*

References for CVE-2018-20783

cvelogic Threat Intelligence