Self-answer: An estate is not a legal entity. Legal title to the assets in the estate are held by the personal representatives of that estate and it is they who can sue or be sued in relation to those assets.
EDITED DISCLAIMER: One of the commenters is concerned that this answer may give the impression that an executor can be held personally liable with the implication that being an executor is a dangerous activity. For the avoidance of doubt, the fact that personal representatives hold legal title which can be the subject of a lawsuit, does not mean in general that they are personally liable. Most lawsuits involving an executor are merely to compel them to dispose of the estate's assets in a particular way (e.g. to pay a creditor or a beneficiary). Those types of lawsuits cannot go beyond the estate's assets and into the executor's personal assets. However, if the executor mismanages the estate, fails to place the creditor's rights ahead of the beneficiary's, pays the beneficiaries incorrectly, spends the estate's assets for himself, or otherwise breaches their fiduciary duties, then they can be held personally liable; in this sense it is quite similar to the way that personal liability works for a trustee or company director. In summary, a well behaved and careful executor will have nothing to worry about, but it also isn't a role to be taken lightly.
On to the full answer:
Authoritative sources
florida Spradley v Spradley 213 So. 3d 1042 (Fla. Dist. Ct. App. 2017:
to the extent that Mr. Spradley attempted to sue his mother's estate,
we find that the trial court erred in failing to grant Mr. Spradley
leave to amend his complaint to substitute the proper party. Although
there does not seem to be a Florida case directly on point, it is
well-settled that "an 'Estate' is not an entity that can be a party to
litigation
[...]
Since estates are not natural or artificial persons, and they lack
legal capacity to sue or be sued, an action against an estate must be
brought against an administrator or executor as the representative of
the estate
new-york DuBois v Beaury No. 1:20-CV-86 (FJS/CFH):
"[U]nder New York law, `[a]n estate is not a legal entity and any
action for or against the estate must be by or against the executor or
administrator in his or her representative capacity.'" Wilmington Tr.,
Nat'l Ass'n v. Estate of McClendon, 287 F. Supp. 3d 353, 373 (S.D.N.Y.
2018) (quoting Visutton Assocs. v. Fastman, 44 Misc. 3d 56, 58, 991
N.Y.S.2d 240, 242 (2d Dep't 2014) (quoting Grosso v. Estate of
Gershenson, 33 A.D.3d 587, 822 N.Y.S. 2d 150, 150 (2d Dep't 2006))
(other citation omitted). Moreover, as the court held in Grosso v.
Estate of Gershenson, 33 A.D.3d 587 (2d Dep't 2006), "[t]he plaintiff
could not bring an action against the decedent's estate since no
executor or administrator had been appointed." Id. at 587.
united-states As noted in DuBois v Beaury, this is a matter for state law, not federal law:
Rule 17(b)(3) of the Federal Rules of Civil Procedure provides, in
pertinent part, that "[c]apacity to sue or be sued is determined. . .
by the law of the state where the court is located.. . . ." Fed. R.
Civ. P. 17(b)(3). Thus, New York law applies to this case.
england-and-wales s 33, Administration of Estates Act 1925:
On the death of a person intestate as to any real or personal estate,
that estate shall be held in trust by his personal representatives
with the power to sell it.
england-and-wales 'Hanbury & Martin: Modern Equity 21st Ed', 2-020:
A legatee or devisee does not, on the testator’s death, become
equitable owner of any part of the estate. The executor takes full
title to the testator’s property, not merely a bare legal estate.
Non-authoritative sources
Wikipedia:
In most circumstances, the executor is the representative of the
estate for all purposes, and has the ability to sue or be sued on
behalf of the estate. The executor holds legal title to the estate
property, but may not use the title or property for their own benefit,
unless permitted by the terms of the will.
florida Florida Probate Trust Litigation Blog:
lawyers speak in terms of suing “the estate,” or transferring property
to “the estate,” or collecting a bill that’s payable by “the estate.”
This kind of loose talk usually doesn’t matter, but sometimes it does.
To be clear, under Florida law there’s no such thing as a separate
legal entity known as an “estate.” If you want to sue, get paid from,
or transfer property to, an “estate,” all of that needs to happen via
the estate’s court-appointed personal representative (PR). [...] This
should be basic stuff, but you’d be surprised how often lawyers (and
judges) get this wrong.
Further point in response to comment
For the avoidance of doubt, the fact that personal representatives hold legal title which can be the subject of a lawsuit, does not mean in general that they are personally liable (i.e. can be compelled to pay out of assets which are not part of the estate). They can be personally liable, but only if they have breached their fiduciary duties.