CVE-2026-45247
CVE-2026-45247 is a security flaw in Mirasvit Full Page Cache Warmer. Attackers can run their own code on Mirasvit Full Page Cache Warmer from anywhere, without logging in. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 3 Jun 2026.[1]
Mirasvit Full Page Cache Warmer is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 1.11.12 of Full Page Cache Warmer for Magento 2.
Description
CISA calls it a full page cache warmer deserialization of untrusted data in Mirasvit Mirasvit Full Page Cache Warmer. In its words: “Mirasvit Full Page Cache Warmer contains a deserialization of untrusted data vulnerability that could allow unauthenticated attackers to achieve remote code execution by supplying a crafted serialized PHP object in the CacheWarmer cookie.”[1]
The CVE record adds: “Mirasvit Full Page Cache Warmer for Magento 2 before version 1.11.12 contains a PHP object injection vulnerability that allows unauthenticated attackers to achieve remote code execution by supplying a crafted serialized PHP object in the CacheWarmer cookie. Attackers can exploit the unrestricted call to PHP's native unserialize() function combined with gadget chains available in Magento and its dependencies to execute arbitrary code on the server.”[2]
The underlying weakness is deserialization of untrusted data (CWE-502), in MITRE’s list of common software weaknesses.
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record lists one fixed version: everything before it is affected.[2]
| Product | Fixed in |
|---|---|
| Full Page Cache Warmer for Magento 2 | 1.11.12 |
Most families won’t have Mirasvit Full Page Cache Warmer; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 3 Jun 2026, 8 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 6 Jun 2026 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 26%. That’s in the top 3% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Mirasvit has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.Mirasvit Full Page Cache Warmer is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 1.11.12 of Full Page Cache Warmer for Magento 2), or not in use. CISA gave US government agencies until 6 Jun 2026 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 26%.[4] |
See also
Other deserialization of untrusted data flaws
- CVE-2021-23758, Ajax.NET Professional: deserialization of untrusted data ·
- CVE-2026-63077, JetBrains TeamCity: deserialization of untrusted data ·
- CVE-2026-50522, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-58644, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-45659, Microsoft SharePoint Server: deserialization of untrusted data ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Mirasvit Full Page Cache Warmer Deserialization of Untrusted Data Vulnerability”. Known Exploited Vulnerabilities Catalog, added 3 Jun 2026.
- ^ National Institute of Standards and Technology. “CVE-2026-45247 Detail”. National Vulnerability Database, published 26 May 2026.
- ^ Mirasvit. Advisories and fixes: mirasvit.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.262, percentile 98.0, 31 Oct 2026.
- CVE Program. “CVE-2026-45247”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.