The remote SUSE Linux SLES11 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2021:14848-1 advisory.

  - Observable response discrepancy in some Intel(R) Processors may allow an authorized user to potentially     enable information disclosure via local access. (CVE-2021-0089)

  - A stack overflow via an infinite recursion vulnerability was found in the eepro100 i8255x device emulator     of QEMU. This issue occurs while processing controller commands due to a DMA reentry issue. This flaw     allows a guest user or process to consume CPU cycles or crash the QEMU process on the host, resulting in a     denial of service. The highest threat from this vulnerability is to system availability. (CVE-2021-20255)

  - x86: TSX Async Abort protections not restored after S3 This issue relates to the TSX Async Abort     speculative security vulnerability. Please see https://xenbits.xen.org/xsa/advisory-305.html for details.
    Mitigating TAA by disabling TSX (the default and preferred option) requires selecting a non-default     setting in MSR_TSX_CTRL. This setting isn't restored after S3 suspend. (CVE-2021-28690)

  - inappropriate x86 IOMMU timeout detection / handling IOMMUs process commands issued to them in parallel     with the operation of the CPU(s) issuing such commands. In the current implementation in Xen, asynchronous     notification of the completion of such commands is not used. Instead, the issuing CPU spin-waits for the     completion of the most recently issued command(s). Some of these waiting loops try to apply a timeout to     fail overly-slow commands. The course of action upon a perceived timeout actually being detected is     inappropriate: - on Intel hardware guests which did not originally cause the timeout may be marked as     crashed, - on AMD hardware higher layer callers would not be notified of the issue, making them continue     as if the IOMMU operation succeeded. (CVE-2021-28692)

  - grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to     certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest     for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest switched     (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the guest these     pages were mapped. The hypervisor tracks only one use within guest space, but racing requests from the     guest to insert mappings of these pages may result in any of them to become mapped in multiple locations.
    Upon switching back from v2 to v1, the guest would then retain access to a page that was freed and perhaps     re-used for other purposes. (CVE-2021-28697)

  - long running loops in grant table handling In order to properly monitor resource use, Xen maintains     information on the grant mappings a domain may create to map grants offered by other domains. In the     process of carrying out certain actions, Xen would iterate over all such entries, including ones which     aren't in use anymore and some which may have been created but never used. If the number of entries for a     given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving     other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e.
    there is no need for multiple domains to be involved here. A pair of cooperating guests may, however,     cause the effects to be more severe. (CVE-2021-28698)

  - Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of     memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime.
    Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing     such pages requires that the hypervisor enforce that no parallel request can result in the addition of a     mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages     that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared,     this similar issue was not noticed. (CVE-2021-28701)

  - grant table v2 status pages may remain accessible after de-allocation (take two) Guest get permitted     access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with     a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest     switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the     guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests     from the guest to insert mappings of these pages may result in any of them to become mapped in multiple     locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed     and perhaps re-used for other purposes. This bug was fortuitously fixed by code cleanup in Xen 4.14, and     backported to security-supported Xen branches as a prerequisite of the fix for XSA-378. (CVE-2021-28703)

  - issues with partially successful P2M updates on x86 T[his CNA information record relates to multiple CVEs;
    the text explains which aspects/vulnerabilities correspond to which CVE.] x86 HVM and PVH guests may be     started in populate-on-demand (PoD) mode, to provide a way for them to later easily have more memory     assigned. Guests are permitted to control certain P2M aspects of individual pages via hypercalls. These     hypercalls may act on ranges of pages specified via page orders (resulting in a power-of-2 number of     pages). In some cases the hypervisor carries out the requests by splitting them into smaller chunks. Error     handling in certain PoD cases has been insufficient in that in particular partial success of some     operations was not properly accounted for. There are two code paths affected - page removal     (CVE-2021-28705) and insertion of new pages (CVE-2021-28709). (We provide one patch which combines the fix     to both issues.) (CVE-2021-28705, CVE-2021-28709)

  - guests may exceed their designated memory limit When a guest is permitted to have close to 16TiB of     memory, it may be able to issue hypercalls to increase its memory allocation beyond the administrator     established limit. This is a result of a calculation done with 32-bit precision, which may overflow. It     would then only be the overflowed (and hence small) number which gets compared against the established     upper bound. (CVE-2021-28706)

  - A flaw was found in the USB redirector device (usb-redir) of QEMU. Small USB packets are combined into a     single, large transfer request, to reduce the overhead and improve performance. The combined size of the     bulk transfer is used to dynamically allocate a variable length array (VLA) on the stack without proper     validation. Since the total size is not bounded, a malicious guest could use this flaw to influence the     array length and cause the QEMU process to perform an excessive allocation on the stack, resulting in a     denial of service. (CVE-2021-3527)

  - An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw     exists in the bootp_input() function and could occur while processing a udp packet that is smaller than     the size of the 'bootp_t' structure. A malicious guest could use this flaw to leak 10 bytes of     uninitialized heap memory from the host. The highest threat from this vulnerability is to data     confidentiality. This flaw affects libslirp versions prior to 4.6.0. (CVE-2021-3592)

  - An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw     exists in the udp_input() function and could occur while processing a udp packet that is smaller than the     size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory     disclosure to the guest. The highest threat from this vulnerability is to data confidentiality. This flaw     affects libslirp versions prior to 4.6.0. (CVE-2021-3594)

  - An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw     exists in the tftp_input() function and could occur while processing a udp packet that is smaller than the     size of the 'tftp_t' structure. This issue may lead to out-of-bounds read access or indirect host memory     disclosure to the guest. The highest threat from this vulnerability is to data confidentiality. This flaw     affects libslirp versions prior to 4.6.0. (CVE-2021-3595)

  - A flaw was found in the USB redirector device emulation of QEMU in versions prior to 6.1.0-rc2. It occurs     when dropping packets during a bulk transfer from a SPICE client due to the packet queue being full. A     malicious SPICE client could use this flaw to make QEMU call free() with faked heap chunk metadata,     resulting in a crash of QEMU or potential code execution with the privileges of the QEMU process on the     host. (CVE-2021-3682)

  - An off-by-one error was found in the SCSI device emulation in QEMU. It could occur while processing MODE     SELECT commands in mode_sense_page() if the 'page' argument was set to MODE_PAGE_ALLS (0x3f). A malicious     guest could use this flaw to potentially crash QEMU, resulting in a denial of service condition.
    (CVE-2021-3930)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-202402-07 (Xen: Multiple Vulnerabilities)

    Multiple vulnerabilities have been discovered in Xen. Please review the CVE identifiers referenced below     for details.

Tenable has extracted the preceding description block directly from the Gentoo Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - grant table v2 status pages may remain accessible after de-allocation (take two) Guest get permitted     access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with     a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest     switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the     guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests     from the guest to insert mappings of these pages may result in any of them to become mapped in multiple     locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed     and perhaps re-used for other purposes. This bug was fortuitously fixed by code cleanup in Xen 4.14, and     backported to security-supported Xen branches as a prerequisite of the fix for XSA-378. (CVE-2021-28703)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Published	Updated	Severity
155812	SUSE SLES11 Security Update : xen (SUSE-SU-2021:14848-1)	Nessus	SuSE Local Security Checks	12/2/2021	7/13/2023	high
189976	GLSA-202402-07 : Xen: Multiple Vulnerabilities	Nessus	Gentoo Local Security Checks	2/4/2024	9/24/2025	high
250439	Linux Distros Unpatched Vulnerability : CVE-2021-28703	Nessus	Misc.	8/18/2025	10/14/2025	high

Detections

Analytics

Plugins Search

high

high

high