CVE-2020-8510: An issue was discovered in phpABook 0.9 Intermediate

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2020-8510 is a critical-severity flaw (CVSS 9.8) affecting phpabook. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in phpABook 0.9 Intermediate. On the login page, if one sets a userInfo cookie with the value of admin+1+en (user+perms+lang), one can login as any user without a password.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Weakness	CWE-287
Published	2020-02-03
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: phpabook project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-02-03 15:15 UTCPublished CVE record published
2026-06-17 03:26 UTCUpdated Record last modified

phpabook project phpabook DOWNGRADE

Affected: 0.9

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.9

1. Check installed version

apt-cache policy phpabook || rpm -q phpabook || phpabook --version

2. No fixed release: DOWNGRADE to a release before 0.9 (Debian / Ubuntu)

apt-cache madison phpabook sudo apt install phpabook=<VERSION_BEFORE_0.9> sudo apt-mark hold phpabook

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list phpabook sudo dnf downgrade phpabook-<VERSION_BEFORE_0.9> sudo dnf versionlock add phpabook

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-8510?

phpabook: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-8510 being exploited?

CVE-2020-8510 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-8510 affect?

CVE-2020-8510 affects phpabook. Severity is critical (CVSS 9.8). An issue was discovered in phpABook 0.9 Intermediate. On the login page, if one sets a userInfo cookie with the value of admin+1+en (user+perms+lang), one can login as any user without a password.

How urgent is CVE-2020-8510?

Priority 57/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2022-30352 CRITICAL 9.8 DOWNGRADE phpABook 0.9i is vulnerable to SQL Injection due to insufficient sanitization of user-supplied data in the "au

References

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