CVE-2021-1905
CVE-2021-1905 is a security flaw in Qualcomm Multiple Chipsets, the chips inside many Android phones. Attackers can corrupt memory in Qualcomm Multiple Chipsets, which they use to take it over. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 3 Nov 2021.[1]
Qualcomm Multiple Chipsets is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Qualcomm has published a fix or advice.
Description
CISA calls it an use-after-free in Qualcomm Multiple Chipsets. In its words: “Multiple Qualcomm Chipsets contain a use after free vulnerability due to improper handling of memory mapping of multiple processes simultaneously.”[1]
The CVE record adds: “Possible use after free due to improper handling of memory mapping of multiple processes simultaneously. in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon Wearables”[2]
The underlying weakness is use after free (CWE-416), in MITRE’s list of common software weaknesses.
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Qualcomm’s advisory has them[3]. CISA names the product as Qualcomm Multiple Chipsets.
Every device with Qualcomm Multiple Chipsets needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 3 Nov 2021, 180 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 3 May 2022 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 2%. That’s in the top 26% 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
Qualcomm has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Update Qualcomm Multiple Chipsets now.Install the latest update from Qualcomm on every device that has it, and restart when asked. Then turn on automatic updates, so the next fix arrives on its own.
- 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 7.8.[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 2%.[4] |
See also
Other Qualcomm Multiple Chipsets flaws
- CVE-2026-21385: memory corruption ·
- CVE-2025-27038: use-after-free ·
- CVE-2025-21480: incorrect authorization ·
- CVE-2025-21479: incorrect authorization ·
- CVE-2024-43047: use-after-free ·
- CVE-2023-33107: integer overflow ·
Other Qualcomm flaws
- CVE-2020-11261, Qualcomm Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon Wearables: multiple chipsets improper input validation ·
Other use after free flaws
- CVE-2026-109619, PHP: stale internal request-state ·
- CVE-2026-109618, PHP: memory corruption ·
- CVE-2026-68820, Microsoft Windows Ancillary Function Driver for WinSock: use-after-free ·
- CVE-2010-0249, Microsoft Internet Explorer: use-after-free ·
- CVE-2020-9715, Adobe Acrobat: use-after-free ·
Added the same day
- CVE-2021-42258, BQE BillQuick Web Suite: SQL injection ·
- CVE-2021-42013, Apache HTTP Server: path traversal ·
- CVE-2021-41773, Apache HTTP Server: path traversal ·
- CVE-2021-40539, Zoho ManageEngine: aDSelfService plus authentication bypass ·
- CVE-2021-40444, Microsoft MSHTML: remote code execution ·
Every Qualcomm flaw on CISA’s list · Everything added in November 2021
References
- ^ Cybersecurity and Infrastructure Security Agency. “Qualcomm Multiple Chipsets Use-After-Free Vulnerability”. Known Exploited Vulnerabilities Catalog, added 3 Nov 2021.
- ^ National Institute of Standards and Technology. “CVE-2021-1905 Detail”. National Vulnerability Database, published 7 May 2021.
- ^ Qualcomm. Advisories and fixes: qualcomm.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.015, percentile 75.0, 31 Oct 2026.
- CVE Program. “CVE-2021-1905”. 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.