What is CVE-2023-34320?A medium-severity flaw in Cortex-A77 Firmware, explained.
CVE-2023-34320 is a medium-severity flaw (CVSS 5.5) in Cortex-A77 Firmware from Arm, published on 8 December 2023. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 0.2%. If you run an affected version, plan in the vendor’s fix.
Published 8 December 2023. Record last updated 4 November 2025. We keep this page's data up to date.
What is CVE-2023-34320? In plain terms.
An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can take it offline.
Cortex-A77 cores (r0p0 and r1p0) are affected by erratum 1508412 where software, under certain circumstances, could deadlock a core due to the execution of either a load to device or non-cacheable memory, and either a store exclusive or register read of the Physical Address Register (PAR_EL1) in close proximity.
What kind of flaw is it?
- CWE-667Improper Locking
How an attack on it works
Read straight from its severity rating, translated out of the shorthand.
- Where an attacker can beAlready on the device
- How hard it is to pull offEasy: no special conditions
- Login needed firstAn ordinary user account
- Does someone have to clickNo, nobody has to do anything
- What an attacker getsCan take it offline
Severity vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is CVE-2023-34320 being exploited? Not that we know of.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.2%. That can change at any time, which is why we keep watching.
Timeline
- Published
- Record last updated
CVE-2023-34320 scores 18. Action: Track.
We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:
- Evidence it is being exploitedBiggest factor
- How severe it isStrong factor
- How widely exposed it isSmaller factor
- Threat activity around itSmaller factor
85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.
When CVE-2023-34320 matches software you track, it lands in your list with its score and the reasons behind it.
See your own ranked list →Who is affected by CVE-2023-34320? 2 products.
The published record lists 2 products from 2 vendors. If you run one of these, check your version, then go to the fix below.
- Operating system
Cortex-A77 Firmware
by Arm
Affected versionsr0p0r1p0 - Operating system
Xen
by Xen
Affected versionsall versions
How do I fix CVE-2023-34320? Four steps.
- Check whether you run itCompare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
- Apply the vendor’s fixInstall the latest update from the vendor. The references list where the vendor has published details.
- If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
- Keep an eye on itTrack the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.
Does CVE-2023-34320 affect you? We'll keep checking.
Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.
- Tell us what you runPick your software from a list, or let us work it out from your website.
- We match it to every flawOver 400,000 published flaws, checked against your list.
- Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
- Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
Free plan, no card needed. Nothing to install.
1 new flaw affects software Acme tracks
Cortex-A77 cores (r0p0 and r1p0) are affected by erratum 1508412 where software, under certain circumstances, could deadlock a core due to the execution of e...
- Matched to
- Cortex-A77 Firmware on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
CVE-2023-34320 is a medium-severity flaw in Cortex-A77 Firmware from Arm, published on 8 December 2023. An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can take it offline.
It scores 5.5 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2023-34320 is 18 out of 100, which is Info. Its action is "Track". No sign of exploitation and a low forecast. Patch it in your normal update cycle.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.2%. That can change at any time, which is why we keep watching.
For Cortex-A77 Firmware from Arm: r0p0, r1p0. The record lists 2 products in all, each with its versions, under "Who is affected" on this page.
Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.