CVE-2021-25395
CVE-2021-25395 is a security flaw in Samsung Mobile Devices, Samsung’s Android phones and tablets. Attackers can get past a security protection in Samsung Mobile Devices. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 29 Jun 2023.[1]
Samsung Mobile Devices is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version SMR MAY-2021 Release 1 of Samsung Mobile Devices.
Description
CISA calls it a race condition in Samsung Mobile Devices. In its words: “Samsung mobile devices contain a race condition vulnerability within the MFC charger driver that leads to a use-after-free allowing for a write given a radio privilege is compromised.”[1]
The underlying weakness is race condition (CWE-362), in MITRE’s list of common software weaknesses.[2]
It scores 6.4 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists one fixed version: everything before it is affected.[2]
| Product | Fixed in |
|---|---|
| Samsung Mobile Devices | SMR MAY-2021 Release 1 |
Every device with Samsung Mobile Devices needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 29 Jun 2023, 748 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 20 Jul 2023 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 under 1%. That’s in the top 70% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Samsung has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions or discontinue use of the product if updates are unavailable”[1]
- Update Samsung Mobile Devices now.On Android: Settings, then System or Software update. Phones only get these fixes while their maker still supports them. Then turn on automatic updates, so the next fix arrives on its own.
- Check you’re on SMR MAY-2021 Release 1 or later.Fixed in version SMR MAY-2021 Release 1 of Samsung Mobile Devices. Anything older is what attackers are going after.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 6.4.[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 under 1%.[4] |
See also
Other Samsung Mobile Devices flaws
- CVE-2025-21042: out-of-bounds write ·
- CVE-2025-21043: out-of-bounds write ·
- CVE-2022-22265: use-after-free ·
- CVE-2021-25489: improper input validation ·
- CVE-2021-25487: out-of-bounds read ·
- CVE-2021-25394: race condition ·
Other Samsung flaws
- CVE-2024-7399, Samsung MagicINFO 9 Server: path traversal ·
- CVE-2025-4632, Samsung MagicINFO 9 Server: path traversal ·
Other race condition flaws
- CVE-2025-39964, Linux Kernel: race condition ·
- CVE-2025-62215, Microsoft Windows: race condition ·
- CVE-2023-36884, Microsoft Windows: search remote code execution ·
- CVE-2014-0196, Linux Kernel: race condition ·
- CVE-2021-0920, Android Kernel: race condition ·
Added the same day
- CVE-2021-25489, Samsung Mobile Devices: improper input validation ·
- CVE-2021-25487, Samsung Mobile Devices: out-of-bounds read ·
- CVE-2021-25394, Samsung Mobile Devices: race condition ·
- CVE-2021-25372, Samsung Mobile Devices: improper boundary check ·
- CVE-2021-25371, Samsung Mobile Devices: unspecified ·
Every Samsung flaw on CISA’s list · Everything added in June 2023
References
- ^ Cybersecurity and Infrastructure Security Agency. “Samsung Mobile Devices Race Condition Vulnerability”. Known Exploited Vulnerabilities Catalog, added 29 Jun 2023.
- ^ National Institute of Standards and Technology. “CVE-2021-25395 Detail”. National Vulnerability Database, published 11 Jun 2021.
- ^ Samsung. Advisories and fixes: security.samsungmobile.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.004, percentile 30.5, 31 Oct 2026.
- CVE Program. “CVE-2021-25395”. 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.