CVE-2021-31537: SIS SIS-REWE Go before 7.7 SP17 allows XSS: rewe/prod/web/index.php (affected parameters are config, version,

Q: How do I fix CVE-2021-31537?

sis-rewe go: upgrade to 7.7. Exact commands for each OS are on this page.

Q: Is CVE-2021-31537 being exploited?

CVE-2021-31537 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-31537 affect?

CVE-2021-31537 affects sis-rewe go. Severity is medium (CVSS 6.1). SIS SIS-REWE Go before 7.7 SP17 allows XSS: rewe/prod/web/index.php (affected parameters are config, version, win, db, pwd, and user) and /rewe/prod/web/rewe_go_check.php (version and all other parameters).

Q: How urgent is CVE-2021-31537?

Priority 50/100. EPSS top 6%: very likely to be exploited; Public exploit reference

This month

MEDIUM 6.1UPGRADE

CVE-2021-31537 is a medium-severity flaw (CVSS 6.1) affecting sis-rewe go. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

SIS SIS-REWE Go before 7.7 SP17 allows XSS: rewe/prod/web/index.php (affected parameters are config, version, win, db, pwd, and user) and /rewe/prod/web/rewe_go_check.php (version and all other parameters).

Why this priority

EPSS top 6%: very likely to be exploited
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	7.4% (top 6%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-05-11
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: sisinformatik

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

Am I affected?

Timeline

2021-05-11 15:15 UTCPublished CVE record published
2026-06-17 03:51 UTCUpdated Record last modified

sisinformatik sis-rewe go UPGRADE

Affected: < 7.7 · 7.7 · 7.7 sp16

Fixed in: 7.7

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy sis-rewe-go || rpm -q sis-rewe-go || sis-rewe-go --version

2. UPGRADE to 7.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sis-rewe-go

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sis-rewe-go

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Nuclei scan template: SIS Informatik REWE GO SP17 <7.7 - Cross-Site Scripting

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-2021-31537?

sis-rewe go: upgrade to 7.7. Exact commands for each OS are on this page.

Is CVE-2021-31537 being exploited?

CVE-2021-31537 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-2021-31537 affect?

CVE-2021-31537 affects sis-rewe go. Severity is medium (CVSS 6.1). SIS SIS-REWE Go before 7.7 SP17 allows XSS: rewe/prod/web/index.php (affected parameters are config, version, win, db, pwd, and user) and /rewe/prod/web/rewe_go_check.php (version and all other parameters).

How urgent is CVE-2021-31537?

Priority 50/100. EPSS top 6%: very likely to be exploited; Public exploit reference

Software pages

PHP vulnerabilities

References

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