CVE-2026-31821: Sylius is an Open Source eCommerce Framework on Symfony

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-31821 is a medium-severity flaw (CVSS 5.3) affecting sylius. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Sylius is an Open Source eCommerce Framework on Symfony. The POST /api/v2/shop/orders/{tokenValue}/items endpoint does not verify cart ownership. An unauthenticated attacker can add items to other registered customers' carts by knowing the cart tokenValue. An attacker who obtains a cart tokenValue can add arbitrary items to another customer's cart. The endpoint returns the full cart representation in the response (HTTP 201). The issue is fixed in

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 91%)
CISA exploited list	No
Weakness	CWE-862
Published	2026-03-10
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: sylius

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

Am I affected?

Timeline

2026-03-10 22:16 UTCPublished CVE record published
2026-06-17 10:34 UTCUpdated Record last modified

sylius sylius UPGRADE

Affected: >= 2.0.0 and < 2.0.16 · >= 2.1.0 and < 2.1.12 · >= 2.2.0 and < 2.2.3

Fixed in: 2.0.16, 2.1.12, 2.2.3

Safe to downgrade to: a release before 2.0.0

1. Check installed version

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

2. UPGRADE to 2.0.16 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sylius

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sylius

Note

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

3. If no update is available yet, DOWNGRADE to a release before 2.0.0 (Debian / Ubuntu)

apt-cache madison sylius sudo apt install sylius=<VERSION_BEFORE_2.0.0> sudo apt-mark hold sylius

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list sylius sudo dnf downgrade sylius-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add sylius

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-2026-31821?

sylius: upgrade to 2.0.16, 2.1.12, 2.2.3. Exact commands for each OS are on this page.

Is CVE-2026-31821 being exploited?

CVE-2026-31821 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-2026-31821 affect?

CVE-2026-31821 affects sylius. Severity is medium (CVSS 5.3). Sylius is an Open Source eCommerce Framework on Symfony. The POST /api/v2/shop/orders/{tokenValue}/items endpoint does not verify cart ownership. An unauthenticated attacker can add items to other registered customers' carts by knowing the

How urgent is CVE-2026-31821?

Priority 26/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-31825 MEDIUM 5.3 UPGRADE Sylius is an Open Source eCommerce Framework on Symfony
CVE-2026-31824 HIGH 8.2 UPGRADE Sylius is an Open Source eCommerce Framework on Symfony
CVE-2026-31823 MEDIUM 4.8 UPGRADE Sylius is an Open Source eCommerce Framework on Symfony
CVE-2026-31822 MEDIUM 6.1 UPGRADE Sylius is an Open Source eCommerce Framework on Symfony
CVE-2026-31820 MEDIUM 6.5 UPGRADE Sylius is an Open Source eCommerce Framework on Symfony

References

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